KR900008034B1 - Motor driven type power steering control device - Google Patents

Abstract

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Description

Motorized Power Steering Control

1 is a schematic diagram showing a configuration of one embodiment of a motor-driven power steering control device of the present invention.

2 is a block diagram of a control unit of one embodiment of FIG.

3 is a control characteristic diagram of steering torque versus motor current for explaining the above embodiment.

4 is a control characteristic diagram of vehicle speed versus motor current and electromagnetic clutch applied voltage.

5 is a control program flowchart of the embodiment.

* Explanation of symbols for main parts of the drawings

1: handle 3 torque detector

9: control unit 9a: steering torque measuring means

9b: vehicle speed measuring means 9c: motor current measuring means

9d: motor current storing means 9e: motor current determining means

9f: Power element opening failure determining means 9g: Electronic clutch control means

9h: power element portion control means 9i: power element portion

9j: current detector 10: vehicle speed detector

12: battery 14: motor

15: electronic clutch 16: reducer

The present invention relates to a motor-driven power steering control device for applying an auxiliary load to the steering device of the vehicle by the rotational force of the motor.

Conventionally, this type of motor-driven power steering control has a structure in which an auxiliary load is applied to a steering shaft or a rack shaft by a transmission mechanism such as a gear or a belt through a driving force of a motor via a speed reducer.

However, such a conventional motor-driven power steering controller has a drawback that only one side of the handle becomes lighter when the power element constituting the power element portion that controls the energization current and direction to the motor is broken.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to prevent the point of lightening of only one of the handles in the event of a power element breakdown, and to obtain a motor-driven power steering controller having high safety even without a significant cost increase. It is aimed.

The motor-driven power steering control apparatus according to the present invention is provided with a control unit which detects the opening of a power element for driving the motor and cuts off the supply current to the motor and the applied voltage to the electromagnetic clutch.

The present invention detects the opening of the power element by the control unit, cuts off the supply current from the power element to the motor by the control unit, and cuts off the voltage applied to the electromagnetic clutch. EMBODIMENT OF THE INVENTION Hereinafter, the Example of the motor-driven power steering control apparatus of this invention is described based on drawing.

1 is a schematic diagram showing the configuration of one embodiment.

In FIG. 1, (1) is a handle which receives a steering rotational force of a driver, and (3) is a torque sensor which outputs an electrical signal according to the rotational force applied to the handle 1. Between the handle 1 and the torque sensor 3, the handle 1 is connected to the first universal joint 4a via the first steering shaft 2a, and the first universal joint 4a is It is connected to the 2nd universal joint part 4b via the 2nd steering shaft 2b. The second universal joint 4b is connected to the torque sensor 3 via the third clause shaft 2c.

The torque sensor 3 is connected to the speed reducer 16 via the fourth steering shaft 2d. The output of the torque detector 3 is sent to the steering torque measuring means 9a (described later in FIG. 2) in the control unit 9.

The reduction gear 16 is inserted between the electromagnetic clutch 15 and the pinion shaft 5. The pinion shaft 5 is engaged with the rack teeth 6a of the rack shaft 6.

Both ends of the rack shaft 6 are connected to the ball joints 8a and 8b via tie rods 7a and 7b, respectively.

On the other hand, reference numeral 12 denotes a vehicle-mounted battery. The negative pole of the battery 12 is grounded and the plus pole is directly connected to the control unit 9 via the key switch 13. The output of the vehicle speed sensor 10 is also input to the control unit 9. The control unit 9 is configured to perform drive control of the motor 14 and the electromagnetic clutch 15. The electromagnetic clutch 15 is capable of engaging or disengaging mechanical communication between the motor 14 and the reducer 16 according to the instruction of the control unit 9.

2 is a configuration diagram showing a specific configuration of the control unit 9 of the first embodiment. In Fig. 2, reference numeral 9a denotes steering torque measuring means for measuring steering torque as an input from the torque detector 3, and 90b denotes vehicle speed measuring means for measuring vehicle speed.

These steering torque measuring means 9a and the vehicle speed measuring means 9b are continuously connected, and the output of the vehicle speed measuring means 9b is sent to the motor current measuring means 9c. The current measuring means 9c measures the energizing current to the motor 14 by the current detector 9j described later.

The motor current storage means 9d stores and holds the current value of the motor 14 corresponding to the steering torque and the vehicle speed.

In general, when the value stored in the motor current storing means 9d is determined to be the value read by the motor current determining means 9e, and the output of the power element opening failure determining means 9f in the next step is an open output. At zero, the motor current determining means 9e determines the current of the motor 14.

The power element opening failure determining means 9f controls the energizing current and the energizing direction to the motor 14 when the motor current measurement value by the motor current measuring means 9c is zero with respect to the energizing current instruction to the motor 14. It judges and outputs that the power element 9i1-9i4 which comprises the power element part 9i is open | released.

The electromagnetic clutch control means 9g performs control for engaging or disengaging the electromagnetic clutch 15 under at least a condition determined by the vehicle speed and an output condition of the power element opening failure determining means 9f. The power element unit control means 9h gives the power element portion 9i an electric current direction direction to the motor 14 and an on / off instruction for controlling the electric current value based on the output of the motor current determination means 9e. It is forever.

The power element unit 9i is composed of first to fourth power elements 9i1 to 9i4 which control the current direction and the current value of the motor 14 based on the output of the power element unit control means 9h. The current value flowing through the power element portion 9i is measured by the current detector 9j.

A voltage corresponding to the current flowing through the current detector 9j is applied to the motor current measuring means 9c.

Next, the operation of the above embodiment will be described with reference to FIGS. 3 is a control characteristic diagram of steering torque vs. motor current, FIG. 4 is a control characteristic diagram of vehicle speed vs. motor current and an electromagnetic clutch applied voltage, and FIG. 5 is a flowchart showing a control program of the control unit 9.

First, when starting the engine and initializing in step S1 of FIG. 5 and turning on the key switch 13, the electromagnetic clutch 15 is turned on, and the motor 14 and the reducer 16 are mechanically connected.

In this state, when the driver applies the rotational force to the handle 1, the control unit 9 controls the current of the motor 14 as shown in FIG. 3 and the steering torque measuring means 9a at the double step S2. ) Receives the output of the torque sensor 3 and measures the steering torque.

In FIG. 3, when the steering torque is increased in the right direction, the motor current I _{OF is} supplied to the motor 14 to turn on the motor 14 at point (a) and to reduce the influence of the inertia of the motor 14 and the mechanical system. The motor current _IMS is measured by the motor current measuring means 9C from the current flowing through the current detector 9j while sending a current (about 2 to 10 A) (step S4).

In addition, the steering torque is increased, and the motor current is linearly increased with respect to the steering torque from the point (b) to become 100% current at the point (c).

On the contrary, if the torque is reduced, the steering torque decreases the motor current than the point (c), and becomes the motor current of I _{OF at} the point (b).

In addition, when the torque is reduced and the point (a) is reached, the motor 14 is turned off. This is almost the same control in the left direction. The relationship of the transmission torque to the motor current is proportional. Accordingly, when the torque is increased in FIG. 3, the motor 14 is turned on at the point (a), and the motor current I _OF flows.

In addition, when the torque is increased, the control is performed to gradually increase the current of the motor 14 from the point (b). Therefore, the output torque to the speed reducer 16 gradually increases, and the auxiliary force corresponding to the driver's force applied to the steering wheel 1 is increased. The torque is transmitted to the rack tooth portion 6a via the electromagnetic clutch 15, the speed reducer 16, and the pinion shaft 5.

For this reason, the handle 1 becomes light. The above is an explanatory diagram for the operation at the time of stopping the vehicle of the present invention.

Next, when the vehicle is in a driving state, the vehicle speed measuring means 9b is measured from the output of the vehicle speed sensor 10 at step S3, and the motor current is measured at step S4, as shown in FIG. as controls the motor current to a current I _M1 in the step (S5) as a current I _M1 to the read motor current determination means (9e) held in the steering torque and the vehicle speed according to the current storage means for holding in advance motor (9d).

The value of the current I _M1 takes the value according to the steering torque only up to the vehicle speed of point (d), and the point (d) or less decreases the value corresponding to the steering torque multiplied by the attenuation rate according to the vehicle speed. : After decelerating vehicle speed V2), to reduce the influence of the inertia of the mechanical system, a constant value I _OF is used.

Next, when the vehicle speed reaches the value of (f) point {vehicle speed = secondary cut-off vehicle speed V1 (V1> V2)}, the motor current and the electromagnetic clutch applied voltage EV become zero, and the motor 14 and the reducer 16 Since the driver is turning the steering wheel 1, the steering is performed without applying an auxiliary load.

By the way, in the conventional apparatus, when the power elements 9i1 to 9i4 constituting the power element unit 9i are damaged, only one side of the handle 1 is light and dangerous.

Therefore, in the present invention, when the motor current detected by the current detector 9j in step S7 at the time of energization command of the motor current is zero, the power element opening failure determination means 9f determines that the power element opening is defective.

If the motor current indication value is zero, the process shifts from step S6 to step S8, and when the vehicle speed V is larger than the auxiliary shut-off vehicle speed V1, i.e., V / V1, the power element control means 9h at step S9. At the same time, the motor current becomes zero, and at step S10, the applied voltage to the electromagnetic clutch 15 is cut off by the electronic clutch control means 9g, and the auxiliary load is not applied. In step S11, the motor current indication value I _M is stored in the I _MO .

If the motor current indication value is not zero in step S6, the flow advances to step S7. If the motor current is zero in step S7, it is determined that the power element opening is defective and the processing in steps S9-S11 is performed. .

In addition, in step S8, if it is not vehicle speed V / V1, in step S12, vehicle speed V is larger than auxiliary reduction vehicle speed V2. That is, if V> V2, the motor current output I _M1 is changed from I _OF to I _M in step S13, and the electromagnetic clutch 15 is controlled by the electromagnetic clutch control means 9g in step S14, and step S11. ) Is executed.

If the vehicle speed is not V > V2 in step S12, the processing of steps S14 and S11 is performed by setting the value of the motor current output I _M to I _M1 in step S15.

According to the present invention, the change of the control program of the control unit detects the opening of the power element and cuts off the current of the motor and the applied voltage of the electromagnetic clutch, so that only one side of the handle is lightened when the power element is damaged. It is possible to increase safety without involving significant cost increase.

Claims (2)

A torque sensor 3 for detecting the rotational force of the vehicle steering wheel 1, a motor supplied with electric current from the vehicle-mounted battery 12, and an electromagnetic clutch 15 for mechanical connection or detachment between the motor and the reducer. In the motor-driven power steering controller which inputs the signals of the said torque sensor 3 and the vehicle speed sensor 10, and controls the said electromagnetic clutch 15 and the motor l4, The electric current supply command of a motor current is provided. When the opening of the power elements 9i1 to 9i4 constituting the power element unit 9i for controlling the energization current and the energization direction of the motor 14 at the time is detected, the current of the motor 14 is blocked and the electromagnetic clutch ( A motor-driven power steering control device comprising a control unit 9 for interrupting the applied voltage of 15). 2. The power supply unit 9 according to claim 1, wherein the control unit 9 is inserted in series with the power element unit 9i and the power element unit 9i for controlling the energization current value and the direction of energization to the motor 14, and energizes the motor. A current detector 9j for detecting a current, a motor current measuring means 9c for measuring a conduction current to the motor 14 with a current detector 9j, and the motor current at the time of energization command to the motor 14 Power element opening failure determination means 9f, power element opening failure determination means 9f, and the power source, wherein the power elements 9i1 to 9i4 determine that the opening is defective when the motor total measured by the measuring means 9c is zero. And a motor-driven power steering control device (9g) for controlling to engage or disengage the electromagnetic clutch (15) under the output condition of the element opening failure determining means (9f).

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