CN108406526B - Active and passive composite flexible polishing method and device - Google Patents

Abstract

After the polishing head is contacted with a workpiece, the contact force is slowly increased, the force is transmitted to a six-dimensional force sensor arranged at the front end of a pull rod hydraulic cylinder by a guide rod and a narrow sliding plate which are fixed on an upper box body, the six-dimensional force sensor collects the contact force information transmitted from the front end of the polishing head, and the telescopic movement of the pull rod is controlled by controlling the oil quantity flowing through the pull rod hydraulic cylinder through adjusting a servo proportional valve so as to change the contact force of the polishing head and the workpiece; a flexible abrasive belt with variable elasticity is adopted. And providing an active-passive composite flexible polishing device. The invention has better adaptability and unlimited application range.

Description

Active and passive composite flexible polishing method and device

Technical field

The invention relates to a polishing method and device, and in particular to a polishing of rotating housing parts.

Background technique

In modern technology, abrasive belt, as a new cost-effective and efficient technology, has become an indispensable processing method in the field of polishing technology. It has high processing efficiency and can be adapted to the polishing of complex special-shaped workpieces. In addition, the cost of use is low, the operation is simple and safe, and the abrasive belt can process not only the materials that the grinding wheel can process, but also some non-ferrous metals and non-metallic soft materials, which makes it extremely widely used. However, there are still many problems in ordinary abrasive belt polishing. For example, during the polishing process, if the contact wheel is too soft, the abrasive grains on the sand surface will easily become dull but not fall off, while a hard contact wheel will cause the abrasive belt to become inseparable from the workpiece. The surface is in rigid contact, and abrasive particles will cause scratches and other processing defects on the surface of the workpiece. In the current force control scheme, the single active force control method has the problem of response lag and cannot fully achieve real-time constant force control. Single passive compliance achieves compliant movement of the workpiece through mechanical devices that can absorb or store energy. However, this compliance method cannot eliminate the problem between the high stiffness of the robot and the high compliance requirements of polishing. And its adaptability is poor, and its scope of use is limited.

Contents of the invention

In order to overcome the shortcomings of existing abrasive belt polishing devices with poor adaptability and limited range of use, the present invention proposes an active-passive composite flexible polishing method and device with good adaptability and unlimited range of use.

The technical solutions adopted by the present invention to solve the technical problems are:

An active-passive composite flexible polishing method. After the polishing head comes into contact with the workpiece, the contact force slowly increases. The force is transmitted from the abrasive belt rod fixed on the upper box to the guide rod fixed on the upper box. , the sliding plate is transmitted to the six-dimensional force sensor installed at the front end of the guide rod of the tie rod hydraulic cylinder. The six-dimensional force sensor collects the contact force information transmitted from the front end of the polishing head, and controls the oil flowing through the tie rod hydraulic cylinder by adjusting the servo proportional valve. The amount is used to control the telescopic movement of the pull rod to change the contact force between the polishing head and the workpiece; a variable elastic flexible abrasive belt is used, which consists of a lower base layer, an elastic layer, a middle base layer, and an abrasive grain layer from bottom to top. When the abrasive belt is tightened, due to the large elastic modulus and small deformation of the base layer, the elastic layer bonded to the base layer has small deformation. In this case, the elastic layer still has a good remainder. Elasticity can provide passive compliance during processing; during the polishing process, when the polishing head contacts the workpiece, the elastically flexible abrasive belt is tightened along the tangential direction of the belt, and the elastic layer of the abrasive belt becomes elastic and flexible. There is still sufficient residual elasticity in the normal direction of the abrasive belt to provide passive contact compliance.

Furthermore, in the elastic flexible abrasive belt, the base material is used as the abrasive and binder carrier. The base material can be cloth base, non-woven fabric, or composite base material, and an elastic layer of a certain thickness is adhered through the base glue. Attached to the base layer, directly plant sand on the elastic layer, choose to continue bonding a layer of base layer above the elastic layer of the elastic flexible sand belt, and then plant sand above the base layer.

The variable elastic flexible abrasive belt adopts a closed structure, and the installation of the abrasive belt is completed through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, driven wheel, and tension wheel controlled by the swing cylinder. During the process, the abrasive belt contacts the workpiece through the contact wheel support at the front end of the abrasive belt rod, and the elastic layer realizes the passive compliance function.

The elastic and flexible abrasive belt that changes during polishing comes into contact with the workpiece through the support of the contact wheel at the front end of the abrasive belt rod. Driven by the mechanical arm, the device has an established spatial path planning; when polishing to different areas, the magnitude of the contact force is unavoidable. will fluctuate, and the fluctuation information of the contact force will be collected by a six-dimensional force sensor installed between the slide plate and the tie rod; a rectangular plate of a slide plate is installed at the front end of the guide rod of the tie rod hydraulic cylinder, and there are holes around the slide plate. The upper body is equipped with an upper guide rod sleeve that allows the guide rod to pass through. Several guide rods are arranged in the device to ensure the linearity of the movement of the tie rod cylinder output to the rectangular plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve A clearance fit is used, which allows the slide plate and the lower guide rod sleeve to reciprocate on the guide rod. The upper guide rod sleeves on the two upper guide rods are connected in a fixed position relative to each other. The upper guide rod sleeve, together with the slide plate and the lower guide rod sleeve, is used. The guide rods move together, and the upper guide rod realizes the movement of the upper box through a fixed connection with the L-shaped structure; by analyzing the deviation between the real-time contact force and the ideal value, the servo proportional valve is adjusted to control the flow through the base plate. The flow rate of the tie rod hydraulic cylinder is controlled to control the expansion and contraction of the guide rod of the tie rod hydraulic cylinder.

A robotic arm is fixedly connected to the base, and the robotic arm is used to complete path planning for surface polishing of different parts; however, when completing the path planning for polishing, the contact force will fluctuate in real time due to changes in the shape and position of the contact surface, but the robotic arm cannot The polishing path is adjusted in real time according to changes in contact force, that is, constant force polishing cannot be achieved.

The servo proportional valve is an electro-hydraulic servo proportional valve. The hydraulic tie rod cylinder is connected to the base plate through bolts. The inlet and outlet of the hydraulic cylinder is connected to the electro-hydraulic servo proportional valve through an oil pipe; a six-dimensional force sensor is installed on the front end of the hydraulic cylinder tie rod. , the information collected by the contact force change is transmitted to the computer, compared with the ideal contact force, and the feedback result is input into the electro-hydraulic servo proportional valve in the form of an electrical signal; the electro-hydraulic servo proportional valve can transmit the low-power electrical signal It is converted into high-power hydraulic energy output to realize the telescopic control of the tie rod.

An active and passive composite flexible polishing device, including an active and passive compliance mechanism, a mechanical arm and a rotating workbench. The active and passive compliance mechanism is installed at the action end of the mechanical arm. The mechanical arm is installed on a base. The active and passive compliance mechanism is installed on the base. The execution end of the compliance mechanism is located on the polishing station of the rotary table;

The active and passive compliance mechanism includes an upper box, a lower box and a bottom plate. The tie rod hydraulic cylinder is fixedly installed on the bottom plate. The guide rod of the tie rod hydraulic cylinder is connected to a six-dimensional force sensor. The other end of the six-dimensional force sensor is connected to the skateboard. , the slide plate and the guide rod on the bottom plate are slidingly connected, and the slide plate and the guide rod of the upper box are fixedly connected to realize the overall linear motion of the upper box and sand belt rod. The servo proportional valve is adjusted to control the flow through the tie rod hydraulic cylinder. The amount of oil is used to control the telescopic movement of the pull rod; the upper box is equipped with a variable elastic flexible abrasive belt, which is composed of a lower base layer, an elastic layer, a middle base layer, and an abrasive layer from bottom to top.

Further, the variable elastic flexible abrasive belt is a closed abrasive belt, and the installation of the abrasive belt is completed through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, driven wheel, and tension wheel controlled by the swing cylinder. The variable elastic flexible abrasive belt is installed through the abrasive belt driving wheel, the driven wheel, the tensioning wheel and the grinding contact wheel installed at the front end of the abrasive belt rod, and the elastic flexible abrasive belt is installed by a spring roller mechanism. The flexible abrasive belt and the abrasive belt rod fit together, and a rotating swing cylinder is used to complete the tensioning of the abrasive belt; there is a groove on the edge of the abrasive belt rod, which cooperates with the blocking fork of the spring roller mechanism, and the blocking fork is stuck on the abrasive belt rod. The grooves prevent the abrasive belt from slipping sideways during processing.

A driven gear is installed on the rotating shaft of the abrasive belt driving wheel, the driven gear meshes with the driving gear, and the driving gear is connected with the output shaft of the driving motor.

Furthermore, a rectangular plate of a sliding plate is installed at the front end of the guide rod of the tie rod cylinder. There are holes around the slide plate, and an upper guide rod sleeve is installed on the hole to allow the guide rod to pass through. The guide rod is arranged in the slide plate to ensure the output of the tie rod cylinder. to the linearity of the movement of the rectangular plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve adopt a clearance fit, which allows the skateboard to reciprocate on the guide rod together with the upper guide rod sleeve, and the two guide rods above The upper guide rod sleeve adopts a relatively fixed connection. The upper guide rod sleeve moves together with the slide plate and the guide rod. The upper guide rod is fixedly connected to the L-shaped structure to realize the movement of the upper box.

In the present invention, the control of the contact force during abrasive belt grinding is achieved by changing the structure of the abrasive belt and adopting an electro-hydraulic servo proportional structure. And cooperate with the spatial path planning capability of the robotic arm to quickly realize the posture and speed control of the device. The robot arm completes the path planning of the polishing process. During the polishing process, the fluctuation information of the contact force between the contact wheel and the workpiece is transmitted to the computer by the six-dimensional force sensor. The computer controls the electro-hydraulic servo proportional valve to realize the tie rod hydraulic cylinder. The expansion and contraction of the guide rod adjusts the relative position between the contact wheel and the workpiece, and changes the size of the contact force. In conjunction with the passive compliance function provided by the invented variable elasticity flexible abrasive belt, active and passive compliance composite polishing of the workpiece is achieved.

The beneficial effects of the present invention are mainly reflected in: better adaptability and no restriction on the scope of use.

Description of the drawings

Figure 1 is an assembly diagram of the present invention.

Figure 2 is a isometric view of the variable elastic flexible abrasive belt of the present invention, in which there is a lower base layer 231, an elastic layer 232, a middle base layer 233, and an abrasive grain layer 234.

Figure 3 is an assembly diagram of the end grinding device of the present invention, in which the upper box 12, the lower box 42 and the bottom plate 43 are included.

Figure 4 is an assembly diagram of the upper box body of the end grinding device of the present invention.

Figure 5 is an assembly diagram of the lower box of the end grinding device of the present invention, in which a is a front view and b is a top view.

Figure 6 is a bottom view of the end of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to Figures 1 to 6, an active and passive composite flexible polishing method is shown. After the polishing head comes into contact with the workpiece, the contact force slowly increases. The force is transmitted from the abrasive belt rod fixed on the upper box to the The guide rod and slide plate on the upper box are transmitted to the six-dimensional force sensor installed on the front end of the guide rod of the tie rod hydraulic cylinder. The six-dimensional force sensor collects the contact force information transmitted from the front end of the polishing head and controls it by adjusting the servo proportional valve. The amount of oil flowing through the tie rod hydraulic cylinder controls the telescopic movement of the guide rod to change the contact force between the polishing head and the workpiece; a variable elastic flexible abrasive belt is used, and the variable elastic flexible abrasive belt consists of an upper base layer, an elastic layer, a middle base layer, The abrasive belt is composed of an abrasive grain layer. When the abrasive belt is tightened, due to the large elastic modulus and small deformation of the base layer, the elastic layer bonded to the base layer has small deformation. In this case, the elastic layer still has a relatively small deformation. Good residual elasticity can provide passive compliance during processing; during the polishing process, when the polishing head contacts the workpiece, the elastic flexible abrasive belt is tightened along the tangential direction of the belt, and the elastic layer of the abrasive belt is There is still sufficient residual elasticity in the normal direction of the variable elastic flexible abrasive belt to provide passive contact compliance.

Furthermore, in the elastic flexible abrasive belt, the base material is used as the abrasive and binder carrier. The base material can be cloth base, non-woven fabric, or composite base material, and an elastic layer of a certain thickness is adhered through the base glue. Attached to the base layer, directly plant sand on the elastic layer, choose to continue bonding a layer of base layer above the elastic layer of the elastic flexible sand belt, and then plant sand above the base layer.

The variable elastic flexible abrasive belt adopts a closed structure, and the installation of the abrasive belt is completed through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, driven wheel, and tension wheel controlled by the swing cylinder. During the process, the abrasive belt contacts the workpiece through the contact wheel support at the front end of the abrasive belt rod, and the elastic layer realizes the passive compliance function.

The elastic and flexible abrasive belt that changes during polishing comes into contact with the workpiece through the support of the contact wheel at the front end of the abrasive belt rod. Driven by the mechanical arm, the device has an established spatial path planning; when polishing to different areas, the magnitude of the contact force is unavoidable. will fluctuate, and the fluctuation information of the contact force will be collected by a six-dimensional force sensor installed between the skateboard and the tie rod; a rectangular plate of a skateboard is installed at the front end of the guide rod of the tie rod cylinder. There are holes around the skateboard. The upper body is equipped with an upper guide rod sleeve that allows the guide rod to pass through. Several guide rods are arranged in the device to ensure the linearity of the movement of the tie rod cylinder output to the rectangular plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve A clearance fit is used, which allows the slide plate and the upper guide rod sleeves to reciprocate on the guide rods. The upper guide rod sleeves on the two upper guide rods are connected in a fixed position relative to each other. The upper guide rod sleeves, together with the slide plate, The guide rods move together, and the upper guide rod realizes the movement of the upper box through a fixed connection with the L-shaped structure; by analyzing the deviation between the real-time contact force and the ideal value, the servo proportional valve is adjusted to control the flow through the base plate. The flow rate of the tie rod hydraulic cylinder is controlled to control the expansion and contraction of the guide rod of the tie rod hydraulic cylinder.

A robotic arm is fixedly connected to the base, and the robotic arm is used to complete path planning for surface polishing of different parts; however, when completing the path planning for polishing, the contact force will fluctuate in real time due to changes in the shape and position of the contact surface, but the robotic arm cannot The polishing path is adjusted in real time according to changes in contact force, that is, constant force polishing cannot be achieved.

The servo proportional valve is an electro-hydraulic servo proportional valve. The hydraulic tie rod cylinder is connected to the base plate through bolts. The inlet and outlet of the hydraulic cylinder is connected to the electro-hydraulic servo proportional valve through an oil pipe; a six-dimensional force sensor is installed on the front end of the hydraulic cylinder tie rod. , the information collected by the contact force change is transmitted to the computer, compared with the ideal contact force, and the feedback result is input into the electro-hydraulic servo proportional valve in the form of an electrical signal; the electro-hydraulic servo proportional valve can transmit the low-power electrical signal It is converted into high-power hydraulic energy output to realize the telescopic control of the tie rod.

An active and passive composite flexible polishing device, including an active and passive compliance mechanism, a mechanical arm and a rotating workbench. The active and passive compliance mechanism is installed at the action end of the mechanical arm. The mechanical arm is installed on a base. The active and passive compliance mechanism is installed on the base. The execution end of the compliance mechanism is located on the polishing station of the rotary table;

The active and passive compliance mechanism includes an upper box, a lower box and a bottom plate. The tie rod hydraulic cylinder is fixedly installed on the bottom plate. The guide rod of the tie rod hydraulic cylinder is connected to a six-dimensional force sensor. The other end of the six-dimensional force sensor is connected to the skateboard. , the slide plate and the guide rod on the bottom plate are slidingly connected, and the slide plate and the guide rod on the upper box are fixedly connected to realize the overall linear motion of the upper box and sand belt rod. The servo proportional valve is adjusted to control the flow through the tie rod hydraulic cylinder. The amount of oil is used to control the telescopic movement of the pull rod; the upper box is equipped with a variable elastic flexible abrasive belt, and the variable elastic flexible abrasive belt is composed of a lower base layer, an elastic layer, a middle base layer, and an abrasive layer.

Further, the variable elastic flexible abrasive belt is a closed abrasive belt, and the installation of the abrasive belt is completed through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, driven wheel, and tension wheel controlled by the swing cylinder. The variable elastic flexible abrasive belt is installed through the abrasive belt driving wheel, the driven wheel, the tensioning wheel and the grinding contact wheel installed at the front end of the abrasive belt rod, and the elastic flexible abrasive belt is installed by a spring roller mechanism. The flexible abrasive belt and the abrasive belt rod fit together, and a rotating swing cylinder is used to complete the tensioning of the abrasive belt; there is a groove on the edge of the abrasive belt rod, which cooperates with the blocking fork of the spring roller mechanism, and the blocking fork is stuck on the abrasive belt rod. The grooves prevent the abrasive belt from slipping sideways during processing.

A driven gear is installed on the rotating shaft of the abrasive belt driving wheel, the driven gear meshes with the driving gear, and the driving gear is connected with the output shaft of the driving motor.

Furthermore, a rectangular plate of a sliding plate is installed at the front end of the guide rod of the tie rod cylinder. There are holes around the slide plate, and an upper guide rod sleeve is installed on the hole to allow the guide rod to pass through. The guide rod is arranged in the slide plate to ensure the output of the tie rod cylinder. to the linearity of the movement of the rectangular plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve adopt a clearance fit, which allows the skateboard to reciprocate on the guide rod together with the upper guide rod sleeve, and the two guide rods above The upper guide rod sleeve adopts a relatively fixed connection. The upper guide rod sleeve moves together with the slide plate and the guide rod. The upper guide rod is fixedly connected to the L-shaped structure to realize the movement of the upper box.

The active and passive composite flexible polishing device of this embodiment includes a robot front end 1, a robot arm 2, a rotating shaft 3, a connecting block 4, a robot arm 5, a rotating table 6, a base 7, a workpiece rotating table 8, a workpiece 9, an active Wheel 10, nut 11, upper box 12, tension wheel 13, tension rod 14, rotary swing cylinder 15, driven wheel 16, nut 17, bolt 18, L-shaped connection 19, spring 20, abrasive belt rod 21, contact Wheel 22, variable elastic flexible abrasive belt 23, fastening screw 24, roller 25, blocking fork 26, screw 27, L-shaped structure 28, upper guide rod sleeve 29, guide rod 30, sliding plate 31, lower guide rod sleeve 32, Base plate 33, tie rod hydraulic cylinder guide rod 34, six-dimensional force sensor 35, tie rod hydraulic cylinder 36, boss 37, gear box 38, driven bevel gear 39, driving bevel gear 40, drive motor 41.

The robotic arm is mounted on the base, and the active and passive compliance mechanism is mounted on the end of the robotic arm. The spatial posture and movement of the active and passive compliance mechanism are realized by controlling the movement of the robotic arm.

The elastic flexible abrasive belt is made of a base material as a carrier of abrasives and adhesives, and the base material can be cloth base, non-woven fabric, or composite base material. An elastic layer is bonded above the base material. The selection of this elastic layer can select the appropriate material according to the workpiece material and grinding parameters in the actual grinding process. For example: styrene-butadiene rubber, SBS and other optional elastic materials. A layer of base glue is bonded above the elastic layer, and a base layer is bonded thereon. On this base layer, abrasives serving as cutting edges and having a grinding effect are implanted. The abrasive material is also selected based on the properties of the workpiece material to be processed and the relevant parameters of grinding. The elastic modulus of the elastic flexible abrasive belt is relatively large in the direction along the tangent line due to the elastic modulus of the base material. During grinding, the tensile force is constant, and the deformation of the elastically flexible abrasive belt is relatively small. At this time, in the direction perpendicular to the movement of the variable elastic flexible abrasive belt, due to the existence of the elastic layer, it can still be linearly elastically deformed in this direction to provide contact flexibility.

There is a round hole at the rear end of the upper box. Under the condition that the output shaft of the motor and the round hole are coaxial, the motor can be mounted on the upper box through bolt connection and the positioning requirements can be achieved at the same time. In the connecting part, a boss is provided on the upper box to enhance the strength and stability of the connecting part. The end of the output shaft of the motor is connected to a set of spur bevel gears to transmit motion to the abrasive belt driving wheel.

On the bevel gearbox on the back of the upper box, the motor is connected to the upper box through bolts. A straight bevel gear is connected to the shaft end of the motor, and another matching straight bevel gear is connected to a shaft connected to the driving wheel. On the coaxial shaft, the spur bevel gear is connected to the shaft through a key to achieve circumferential positioning, and matches the nut to achieve axial positioning. During the polishing process, the power of the servo motor is transmitted to the driving grinding wheel shaft through the bevel gear. The driving grinding wheel shaft realizes circumferential positioning with the driving grinding wheel through a key connection, and transmits the motion on the shaft to the driving grinding wheel. The active grinding wheel in the box drives the elastic flexible sand belt to move. A gearbox is installed on the bevel gear of the upper box to prevent the bevel gear from being contaminated by wear debris during movement and affecting its service life.

There is an electro-hydraulic servo proportional control device under the upper box. The device uses a tie rod cylinder as the output element at the end. The tie rod hydraulic cylinder is connected to the bottom plate through bolts. An L-shaped connection is installed on the base plate, and one side is provided for bolt connection. The L-shaped structure is connected to the base plate through bolt connection. The other half has holes for connecting the upper guide rod sleeve, the guide rod matches the upper guide rod sleeve, and the upper guide rod sleeve matches the L-shaped connection. Above the base plate, there is the same L-shaped connection. The L-shaped connection is connected to the upper box body through bolts. The hole on the other side matches the upper guide rod sleeve, and the upper guide rod sleeve matches the guide rod.

In the guide rod mechanism, the shaft end of the telescopic shaft of the tie rod cylinder is connected to a six-dimensional force sensor, and the other side of the six-dimensional force sensor is connected to the rectangular sliding plate. There are holes around the rectangular slide plate that match the four guide rods. They are connected through shaft sleeves. The shaft sleeves are fixedly connected to the slide plate. The two upper guide rod sleeves are fixedly connected to the guide rods. The two upper guide rod sleeves are fixedly connected to the guide rods. The lower guide rod sleeve and the guide rod have a clearance fit, which can achieve relative sliding and ensure linear motion.

The contact wheel is mounted on the front end of the above-mentioned abrasive belt rod through a fixed rotating shaft. The contact wheel has a certain size, and after being installed on the abrasive belt rod, it forms a tangent with the inclined edge line of the abrasive belt rod. There is a groove on the edge of the abrasive belt rod. The spring roller mechanism in this device is used in conjunction with it to pre-tighten and position the elastic abrasive belt laterally to prevent the abrasive belt from deflecting during the polishing process. Precision. It has a good effect on improving the polishing quality of workpieces.

The bolt is connected to the block fork and passes through the spring, and is connected to the front end of the L-shaped connection through a nut. By twisting the nut, the spring forms a certain pre-pressure. Place a cylindrical roller in the U-shaped groove below the fork. Under the action of spring and pressure, the cylindrical roller completes the pre-tightening of the abrasive belt and abrasive belt rod. The L-shaped connection is connected to the upper box via screws.

On the right side of the upper box, there are two rotating shafts of the abrasive belt wheels. A swing cylinder is installed on the far right side. The rotating swing cylinder is used to drive the tension wheel to rotate by controlling the rotating rod to realize the elastic flexible abrasive belt. of tension. An abrasive belt rod is installed on the left side of the upper box body. The abrasive belt rod is connected by screws and fixed on the upper box body. Install the motor on the back corresponding to the driving wheel of the upper box, and set up a gearbox to avoid contamination by machining wear debris. On the other side of the motor, install a tie rod cylinder to balance the counterweights on both sides. Keeping the size of the assembly as small as possible will help maximize the spatial positional movement of the device at the end of the robotic arm without being limited by the size of the device itself.

The technical solutions and effects of the present invention will be made clearer and clearer by further describing the specific implementation modes of the patent of the present invention in conjunction with the accompanying drawings.

This embodiment takes polishing of the rotary housing workpiece 9 as an example. As shown in Figures 1 to 6, a workpiece 9 is installed above the workpiece rotating table 8. The mechanical arm is installed on the base 7, and the active and passive compliance mechanism is installed at the end of the mechanical arm. In the upper box, the variable elastic flexible abrasive belt 23 adopts a closed structure and passes through the abrasive belt driving wheel 10, the driven wheel 16, the tensioning wheel 13 and the grinding contact wheel 22 installed at the front end of the abrasive belt rod 21 to achieve Installation of variable elastic flexible abrasive belts. The spring roller mechanism is used to realize the fitting of the elastic flexible sand belt 23 and the sand belt rod 21, and the rotating swing cylinder 15 is used to complete the tensioning of the sand belt. There is a groove on the edge of the abrasive belt rod 21, which matches the blocking fork 26 of the spring roller mechanism. The blocking fork 26 is stuck in the groove of the abrasive belt rod 21 to prevent the abrasive belt from slipping sideways during processing. Improve the stability of the abrasive belt operation to improve the surface accuracy of grinding. Below the upper box, there is a drive motor 41 for placing the driving abrasive pulley and the transmission bevel gears 39 and 40. Two guide rods are connected to the upper box through bolts. Here the two guide rods 30 and the upper guide rod sleeve 29 It is a fixed connection, and the upper guide rod sleeve 29 and the sliding plate 31 are also a fixed connection. At the same time, two guide rods and a lower guide rod sleeve 32 used in conjunction with the base plate are also connected. The two guide rods connected to the base plate and the lower guide rod sleeve 32 have a clearance fit that can relatively slide. At this time, the upper guide rod There is a fixed connection between the rod sleeve 29 and the sliding plate. A tie rod hydraulic cylinder 36 is installed on the bottom plate. The guide rod end of the tie rod hydraulic cylinder 36 is equipped with a six-dimensional force sensor 35. The other end of the six-dimensional force sensor used is connected to the skateboard, and the skateboard is connected to the four guide rods mentioned above. set.

During the machining process, the rotary table 8 drives the workpiece 9 to perform rotational motion of the fixed axis. The relative speed between the workpiece and the abrasive belt during the polishing process can be adjusted by adjusting the rotational speed of the rotary table. The polishing device proposed in the present invention is driven by the mechanical arm to realize the adjustment of the spatial posture. In this example, for the rotary shell workpiece 9, the polishing path planning of the polishing head is implemented. The polishing head slowly approaches the starting processing point of the target workpiece and feeds slowly. Until the flexible flexible abrasive belt 23 is attached to the workpiece under the support of the contact wheel 22 . Due to the elasticity of the variable elastic flexible abrasive belt 23, passive compliance in processing can be achieved. The device moves according to the established spatial processing path under the control of the robotic arm. During the machining process, since the contact force between the abrasive belt and the workpiece has a great influence on the surface quality of the processing, where the contact force fluctuates greatly, the force changes are transmitted through the abrasive belt rod 21, the upper box, and the guide rod 30 , the skateboard 31 is transmitted to the six-dimensional force sensor 35. The six-dimensional force sensor 35 transmits the force change information to the computer in real time. The computer transmits the electrical signal to the electro-hydraulic servo proportion by comparing the deviation between the actual value and the ideal value. valve. The electro-hydraulic servo proportional valve converts low-power electrical signals into high-power hydraulic energy output, controls the inlet and outlet flow through the tie rod hydraulic cylinder, and realizes the telescopic movement of the tie rod hydraulic cylinder guide rod 34. The slide plate 31 moves together with the tie rod hydraulic cylinder guide rod 34 and the six-dimensional force sensor 35 to drive the upper box to make a feed motion in the linear direction. The change in the relative position between the polishing head and the workpiece directly changes the size of the contact force, and The six-dimensional force sensor at the end of the tie rod hydraulic cylinder guide rod 34 is still collecting contact force information. The electro-hydraulic servo proportional valve can complete the dynamic response in a very short time, avoiding the hysteresis of active compliance and achieving this polishing The device provides real-time control of contact force during polishing. This polishing device has well realized the combined use of active and passive compliance functions, which improves the adaptability of the device to process workpieces with high contact force requirements. The strong adaptability of the mechanical arm to the path enables the device to complete polishing well.

Claims (7)

1. An active and passive composite flexible polishing method, which is characterized in that after the polishing head comes into contact with the workpiece, the contact force slowly increases, and the force is transmitted from the abrasive belt rod fixed on the upper box to the abrasive belt rod fixed on the upper box. The guide rod and slide plate on the box are transmitted to the six-dimensional force sensor installed on the front end of the guide rod of the tie rod hydraulic cylinder. The six-dimensional force sensor collects the contact force information transmitted from the front end of the polishing head and controls the flow by adjusting the servo proportional valve. The oil volume of the tie rod hydraulic cylinder is used to control the telescopic movement of the guide rod to change the contact force between the polishing head and the workpiece; a variable elastic flexible abrasive belt is used, which consists of a lower base layer and an elastic layer from bottom to top. , a middle base layer and an abrasive grain layer. When the abrasive belt is tightened, due to the large elastic modulus and small deformation of the base layer, the elastic layer bonded to the base layer has small deformation. In this case, the elasticity The layer still has good residual elasticity, which can provide passive compliance during processing; during the polishing process, when the polishing head contacts the workpiece, the elastic flexible abrasive belt is tightened along the tangential direction of the belt. The elastic layer of the belt still has sufficient residual elasticity in the normal direction of the variable elastic flexible abrasive belt to provide passive contact compliance; In the variable elastic flexible abrasive belt, the base material is used as the abrasive and binder carrier. The base material can be cloth base, non-woven fabric, or composite base material, and a certain thickness of elastic layer material is adhered through the primer. On the base layer, choose to continue to bond a layer of base layer above the elastic layer of the elastic flexible sand belt, and then plant sand on top of the base layer; The variable elastic flexible abrasive belt adopts a closed structure, and the installation of the abrasive belt is completed through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, driven wheel, and tension wheel controlled by the swing cylinder. During the process, the abrasive belt contacts the workpiece through the contact wheel support at the front end of the abrasive belt rod, and the elastic layer realizes the passive compliance function. 2. The active and passive composite flexible polishing method as claimed in claim 1, characterized in that: the flexible elastic abrasive belt that changes during polishing contacts the workpiece through the support of the contact wheel at the front end of the abrasive belt rod, and the device is driven by a mechanical arm and has a predetermined spatial path planning; when polishing to different areas, the size of the contact force will inevitably fluctuate, and the fluctuation information of the contact force will be collected by a six-dimensional force sensor installed between the slide plate and the guide rod of the tie rod hydraulic cylinder; A rectangular plate with a sliding plate is installed at the front end of the guide rod of the tie rod hydraulic cylinder. There are holes around the slide plate, and an upper guide rod sleeve is installed on the hole to allow the guide rod to pass. Several guide rods are arranged in the device to ensure that the tie rod cylinder The linearity of the movement output to the rectangular plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve adopt a clearance fit, which allows the skateboard to reciprocate on the guide rod together with the upper guide rod sleeve, and the two upper guide rods The upper guide rod sleeve adopts a relatively fixed connection. The upper guide rod sleeve moves together with the slide plate and the guide rod. The upper guide rod is fixedly connected to the L-shaped connector to realize the movement of the upper box; through Analyze the deviation between the real-time contact force and the ideal value, adjust the servo proportional valve to control the flow through the tie rod hydraulic cylinder installed on the base plate, and then control the expansion and contraction of the tie rod hydraulic cylinder guide rod. 3. The active and passive composite flexible polishing method according to claim 2, characterized in that: a mechanical arm is fixedly connected to the base, and the mechanical arm is used to complete path planning for surface polishing of different parts; however, when the path planning is completed for polishing , due to changes in the shape and position of the contact surface, the contact force will fluctuate in real time. However, the robotic arm cannot make real-time adjustments to the polishing path according to changes in the contact force, that is, constant force polishing cannot be achieved. 4. The active and passive composite flexible polishing method according to claim 1, characterized in that: the servo proportional valve is an electro-hydraulic servo proportional valve, the hydraulic tie rod cylinder is connected to the base plate through bolts, and the inlet and outlet of the hydraulic cylinder pass through The oil pipe is connected to the electro-hydraulic servo proportional valve; a six-dimensional force sensor is installed on the front end of the hydraulic cylinder pull rod. The information collected by the contact force change is transmitted to the computer, which is compared with the ideal contact force and the feedback result is input into the electronic circuit in the form of an electrical signal. Hydraulic servo proportional valve; electro-hydraulic servo proportional valve can convert the transmitted low-power electrical signal into the output of high-power hydraulic energy to realize the telescopic control of the tie rod. 5. A polishing device that implements the active and passive composite flexible polishing method as claimed in claim 1, characterized in that: the polishing device includes an active and passive compliance mechanism, a mechanical arm and a rotating workbench, and the active and passive compliance mechanism is installed At the action end of the robotic arm, the robotic arm is installed on the base, and the execution end of the active and passive compliance mechanism is located on the polishing station of the rotary workbench; The active and passive compliance mechanism includes an upper box, a lower box and a bottom plate. The tie rod hydraulic cylinder is fixedly installed on the bottom plate. The guide rod of the tie rod hydraulic cylinder is connected to a six-dimensional force sensor. The other end of the six-dimensional force sensor is connected to the skateboard. , the slide plate and the guide rod on the bottom plate are slidingly connected, and the slide plate and the guide rod on the upper box are fixedly connected to realize the overall linear motion of the upper box and sand belt rod. The servo proportional valve is adjusted to control the flow through the tie rod hydraulic cylinder. The amount of oil is used to control the telescopic movement of the guide rod; the upper box is equipped with a variable elastic flexible abrasive belt, which is composed of a lower base layer, an elastic layer, a middle base layer, and an abrasive layer from bottom to top; A rectangular plate with a sliding plate is installed at the front end of the guide rod of the tie rod hydraulic cylinder. There are holes around the slide plate, and an upper guide rod sleeve is installed on the hole to allow the guide rod to pass. The guide rod is arranged in the slide plate to ensure that the tie rod cylinder outputs to the rectangular The linear motion of the plate; in addition, the guide rod close to the bottom plate and the lower guide rod sleeve adopt a clearance fit, which allows the skateboard to reciprocate on the guide rod together with the upper guide rod sleeve, and the upper guide rods on the two upper guide rods The guide rod sleeve adopts a relatively fixed connection. The upper guide rod sleeve moves together with the slide plate and the guide rod. The upper guide rod is fixedly connected to the L-shaped connector to realize the movement of the upper box. 6. The polishing device according to claim 5, characterized in that: the variable elastic flexible abrasive belt is a closed abrasive belt, which passes through the abrasive belt driving wheel, spring roller mechanism, contact wheel, spring roller mechanism, and driven wheel. , the tensioning wheel controlled by the swing cylinder completes the installation of the abrasive belt. The variable elastic flexible abrasive belt passes through the abrasive belt driving wheel, the driven wheel, the tension wheel and the grinding contact wheel installed at the front end of the abrasive belt rod to achieve variable elastic flexible sanding. The belt is installed, and the spring roller mechanism is used to realize the fit between the flexible flexible abrasive belt and the abrasive belt rod, and a rotating swing cylinder is used to complete the tensioning of the abrasive belt; there is a groove on the edge of the abrasive belt rod, which cooperates with the spring The blocking fork of the roller mechanism is stuck in the groove of the abrasive belt rod to prevent the abrasive belt from slipping sideways during processing. 7. The polishing device according to claim 6, characterized in that: a passive gear is installed on the rotating shaft of the abrasive belt driving wheel, the passive gear meshes with the driving gear, and the driving gear is connected with the output shaft of the driving motor.