Low speed autonomous steering controller and method

Abstract

The application discloses a low-speed unmanned steering controller and method, the controller comprises a main control unit CPU and a pre-drive circuit, the output end of the main control unit CPU is connected with the pre-drive circuit, and the pre-drive circuit is used for driving the action of a steering motor; the controller further comprises a magnetic induction angle chip, a corresponding sensor magnet of the magnetic induction angle chip is arranged on a motor output shaft, the magnetic induction angle chip acquires an angle signal by analyzing a sensor magnet signal, and the output end of the magnetic induction angle chip is connected with the main control unit CPU. The steering controller is stable and reliable, the angle detection of the steering motor is performed by using a magnet and an angle sensor chip, the installation and production are simpler, the complicated installation process of the sensor body in the prior art is solved, and the manufacturing period of the steering controller is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steering control, in particular to a low-speed unmanned steering controller. BACKGROUND

[0002] Unmanned technology is one of the future development directions of automobiles, and it is expected that in the future unmanned vehicles will become safe transportation tools in people's lives. However, the development of unmanned technology is not as smooth as we expected. Unmanned development needs to comply with three laws, namely, low speed first, then high speed, carry goods first, then carry people, and commercial use first, then civilian use. Among them, low-speed unmanned is considered by the industry to be the field that can achieve the fastest application landing and scale replication. In the existing technology of unmanned technology, based on camera and or radar monitoring data, the vehicle is controlled by the vehicle controller such as the domain controller to identify and control the vehicle, such as the application number: 202110031888.5, a method for controlling an unmanned vehicle, comprising obtaining the driving route of the unmanned vehicle and the current driving lane; determining whether the unmanned vehicle has a lane change demand; if so, determining the trigger target of the lane change demand; determining the target lane; obtaining the non-merge section from the trigger target that is continuous and cannot be merged into the target lane; obtaining the distance of the unmanned vehicle from the non-merge section; determining whether the distance is less than or equal to the preset threshold; if so, detecting whether the unmanned vehicle meets the conditions for merging into the target lane; if so, controlling the unmanned vehicle to merge into the target lane, and if not, performing the step of obtaining the distance of the unmanned vehicle from the non-merge section, so that when there is a non-merge section on the target lane, the unmanned vehicle merges into the target lane at a certain distance from the non-merge section, thereby ensuring the normal driving of the unmanned vehicle.

[0003] An important part of unmanned technology is the control of the direction of the vehicle, which requires the use of a steering controller. The existing unmanned controller solution is to use a non-contact angle sensor welded on the input shaft and then connected to the controller through a lead to achieve the angle command. This not only has strict requirements on the structure and installation, but also has a complicated process, and the sensor needs to be calibrated after installation. The precision of the body is not high. Due to the lead being easily affected by environmental electromagnetic interference, it is prone to short circuit, open circuit and other risks. Such a solution process is complex, risky, costly and inefficient. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a low-speed unmanned steering controller. The controller uses magnetic induction to obtain the angle signal of the low-speed unmanned vehicle and controls the vehicle.

[0005] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a low-speed unmanned steering controller, the controller comprising a main control unit CPU and a pre-drive circuit, the output end of the main control unit CPU being connected to the pre-drive circuit, for driving the action of a steering motor through the pre-drive circuit; the controller further comprising a magnetic induction angle chip, a corresponding sensor magnet of the magnetic induction angle chip being arranged on a motor output shaft, the magnetic induction angle chip acquiring an angle signal by analyzing a sensor magnet signal, and the output end of the magnetic induction angle chip being connected to the main control unit CPU.

[0006] The magnetic induction angle chip is connected to the main control unit CPU through a main-backup two-way transmission interface.

[0007] The controller further comprising a power supply circuit, the input end of the power supply circuit being used for being connected to a battery BAT; the output end of the power supply circuit outputting a direct current power supply for powering the controller; the power supply circuit having an enable end EN, the enable end EN of the power supply circuit being configured as an input ignition signal.

[0008] The controller further comprising a relay K1 and a pre-charge circuit, the battery BAT being connected to the pre-drive circuit through the relay, for powering the pre-drive circuit, and the output end of the main control unit CPU being connected to the control end of the relay K1 and the control end of the pre-charge circuit respectively.

[0009] The pre-charge circuit comprising a pre-charge resistor R1 and a triode Q1, the battery BAT leading out a drive power supply terminal through the normally open contact of the relay K1, the drive power supply terminal being used for being connected to the power supply end of the pre-drive circuit; a terminal being led out between the battery BAT and the normally open contact of the relay K1 and being connected to the anode of a diode D1, the cathode of the diode D1 being connected to one end of the pre-charge resistor R1 through a triode, the other end of the resistor R1 being connected to the drive power supply terminal; a terminal being led out from the cathode of the diode D1 and being connected to one end of the coil of the relay K1 through a triode Q2, the other end of the coil of the relay K1 being grounded; and the output end of the main control unit CPU being connected to the control end of the triodes Q1 and Q2 respectively for controlling the conduction and disconnection of the triodes Q1 and Q2.

[0010] The pre-drive circuit comprising a gate drive and a bridge circuit composed of four MOSs;

[0011] The main control unit CPU being connected to the gate of each MOS in the bridge circuit through the gate drive; and the output end of the bridge circuit being connected to the steering motor.

[0012] The controller further comprising a CAN communication circuit, the main control unit CPU being connected to the vehicle-mounted controller of a vehicle through the CAN communication circuit.

[0013] The controller further comprises a temperature monitoring circuit for detecting the temperature of the controller, and the output end of the temperature monitoring circuit is connected to the main control unit CPU.

[0014] The controller further comprises a voltage current / voltage sampling circuit for collecting the current and voltage of the steering motor, and the output end of the voltage current / voltage sampling circuit is connected to the main control unit CPU.

[0015] The main control unit CPU is connected with a memory, and the memory is an EEPROM.

[0016] The steering controller has the advantages that: the steering controller is stable and reliable, the angle of the steering motor is detected by using a magnet plus an angle sensor chip, the installation and production are simpler, the complicated installation process of the sensor body in the prior art is solved, and the manufacturing period of the steering controller is shortened; the angle of the steering motor is detected by using the magnet plus the angle sensor chip, the risks of wire harness open circuit, short circuit and electromagnetic interference are reduced, the procurement cost is greatly reduced, the sensor angle detection accuracy is high, and the response is fast; the controller is integrated with a pre-charging circuit for controlling the power supply of a pre-driving circuit, the contact problem of a relay for charging control caused by direct power supply is avoided; the controller is integrated with a temperature monitoring circuit inside, and the temperature of the controller can be monitored and protected. The steering controller is controlled based on a starting signal, and the power-on work of the steering controller after starting is realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] The content expressed by each drawing of the present application and the marks in the drawings are briefly described as follows:

[0018] Figure 1 It is a whole frame principle diagram of the steering controller of the present application;

[0019] Figure 2 It is a principle diagram of the power supply circuit of the steering controller of the present application;

[0020] Figure 3 It is a principle diagram of the pre-charging circuit and the relay K1 for the power supply of the pre-driving circuit of the present application;

[0021] Figure 4 It is a principle diagram of the pre-driving circuit of the present application;

[0022] Figure 5 It is a principle diagram of the CAN communication circuit of the present application;

[0023] Figure 6 It is a principle diagram of the angle sensor of the present application;

[0024] Figure 7 It is a principle diagram of the temperature monitoring circuit of the present application;

[0025] Figure 8The principle diagram of the output PWM of the controller controlling the motor;

[0026] Figure 9 The steering speed F / B control principle diagram. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0028] The embodiment designs an unmanned steering controller, the angle acquisition sensor in the steering controller is realized by using a magnetic induction sensor, so that the angle signal can be obtained without leading out a wire from the steering motor, thereby greatly reducing the wiring cost and difficulty; meanwhile, the circuit in the controller is designed, so that the accurate and reliable steering control of the controller circuit is realized while the stable work of the controller circuit is ensured.

[0029] The specific scheme is as follows:

[0030] As shown in Figure 1 A low-speed unmanned steering controller, the controller includes a main control unit CPU, a pre-drive circuit and a magnetic induction angle chip, the output end of the main control unit CPU is connected to the pre-drive circuit, which is used to drive the action of the steering motor through the pre-drive circuit; the main control unit CPU is the core of the controller and is used to realize the control and processing functions of the whole system, the output end of the main control unit CPU is connected to the steering motor through the pre-drive circuit, so as to realize the control of the motor. The main control unit CPU can be realized by a microprocessor such as a single-chip microcomputer, and can be selected from the Cortex-M0+, 32-bit CPU series single-chip microcomputer according to actual needs.

[0031] Since the control of the motor needs an angle signal, the steering angle acquisition and processing circuit is integrated in the controller, the steering angle acquisition and processing circuit adopts a magnetic induction scheme, which includes a magnetic induction angle chip integrated in the controller and a magnet arranged on the output shaft of the steering motor, the corresponding sensor magnet of the magnetic induction angle chip is arranged on the output shaft of the motor, the magnetic induction angle chip obtains the angle signal by analyzing the sensor magnet signal, and the output end of the magnetic induction angle chip is connected to the main control unit CPU. The main control unit CPU drives the motor to rotate through the pre-drive circuit according to the steering control instruction from the upper computer, and adjusts and controls through the feedback of the acquired motor angle.

[0032] The sensor magnet is installed on the output shaft, and then the angle change is analyzed through the magnetic induction angle chip on the controller, and the CPU of the main control unit realizes the driving control of the steering motor according to the angle; in order to ensure that the angle signal output by the magnetic induction chip can be reliably transmitted to the CPU of the main control unit, the magnetic induction angle chip is connected to the CPU of the main control unit through two transmission interfaces of main and standby, and the two circuits are connected to the SPI interface of the CPU of the main control unit through two SPI communication circuits.

[0033] As shown in Figure 6 , the magnetic induction angle sensor includes a sensor chip and a magnet, and the angle sensor circuit adopts a magnetic angle sensor chip for McGann automotive application; MT6511GT is used, and double-channel output ASIL-D level is adopted, when one angle signal fails, the other can continue to be used; it is mainly used in cooperation with the sensor magnet, and the magnet is installed on the output shaft for angle identification. The sensor chip MT6511GT chip obtains the angle signal according to the induction signal between the magnets and outputs the corresponding angle signal to the main control CPU through two-way output mode, and the two-way circuit of its output end is 8, 7, 12 pins and 16, 14, 4 pins.

[0034] The main control CPU and other components in the controller of the application are powered by a power supply circuit, and the power supply circuit DCDC is integrated in the controller; the input end of the power supply circuit is used for connecting to the battery BAT; the output end of the power supply circuit outputs direct current power supply for the controller; the power supply circuit has an enable end EN, and the enable end EN of the power supply circuit is configured as an input ignition signal. The power supply circuit uses DCDC chip to convert the voltage of the battery into low voltage required by each part in the controller, such as 5V voltage for CPU power supply. The DCDC has an enable end input ignition signal, which can realize starting work after ignition, realize the power-on work of the steering controller after ignition, and ensure that the steering controller can provide quick and accurate power assistance control after ignition.

[0035] As shown in Figure 2 , the chip used by DC-DC is LN10261Q1-11-EFR; the chip has a high input voltage of 60V, and the output voltage range can be adjusted, and the design output voltage is 5V, which is used for power supply of system MCU and power supply of other chips. The chip has an EN enable pin which can be used for ignition enable and power supply retention. In Figure 2The diagram shows the pinout and peripheral circuitry of the DC-DC chip U2. Pin 8 (SW) of chip U2 is the output pin, leading to a +5V output via inductor L3 to power the CPU. Pin 7 is connected to pin 8 via capacitor C28. Pin 6 of U2 is grounded via capacitor C33. The FB pin is the adjustment pin; the +5V output of the DC-DC chip is grounded via resistors R29 and R36 in series, with a terminal connecting to the FB pin for feedback control of the output acquisition. The +5V output pin is grounded via a capacitor for filtering. The RT pin is grounded via resistor R34. Pin 2 is the VIN port, used for inputting the battery voltage and connected to the battery BAT. Pin 3 (EN) is the enable pin, connected to the pins of diodes D8 and D9. The anode of D8 is connected to the ignition signal via a resistor, and the anode of D9 is connected to the VCTRL ON signal via resistor R41, which is the control enable signal. This enables both ignition and controlled enable operation.

[0036] Furthermore, the steering controller of this application integrates a relay K1 for powering the pre-drive circuit and a pre-charge circuit, such as... Figure 1 As shown, the battery BAT is connected to the pre-drive circuit via a relay to supply power to the pre-drive circuit. The output of the main control unit CPU is connected to the control terminal of the relay K1 and the control terminal of the pre-charge circuit respectively. Before powering the pre-drive circuit, the pre-charge circuit is started first, and then the relay is controlled to work and the pre-charge circuit is disconnected. This provides protection for the relay K1.

[0037] like Figure 3 As shown, the pre-charging circuit includes a pre-charging resistor R1, transistors Q1 and Q2. The battery BAT output power terminal VBAT+ is led out to the drive power supply terminal through the normally open contact of relay K1. The drive power supply terminal is used to connect to the power supply terminal of the pre-drive circuit. Before the battery voltage is input to the normally open contact, resistor R3, capacitor C4 and TVS transistor D4 are set to ensure safety. VBAT+ is grounded through resistor R6. Capacitors C4 and D4 are connected in parallel across resistor R6. Capacitor R3 is set between VBAT+ and the normally open contact.

[0038] The terminal between the battery VBAT+ terminal and the normally open contact of the relay K1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to one end of the pre-charge resistor R1 through a transistor, the other end of the resistor R1 is connected to the driving power supply terminal for supplying power to the pre-driving circuit; the terminal from the cathode of the diode D1 is connected to one end of the coil of the relay K1 through the transistor Q2, the other end of the coil of the relay K1 is connected to the ground and the anode of the diode D2, the cathode of the diode D2 is connected between the coil and Q2; the output of the main control unit CPU is connected to the control end of the transistors Q1 and Q2 respectively for controlling the conduction and disconnection of the transistors Q1 and Q2. The main control CPU can realize the opening and closing of the pre-charge and the starting work of the relay K1 by driving the conduction of the transistors Q1 and Q2; when Q1 is closed, the pre-charge circuit is opened, otherwise the pre-charge circuit is closed; Q2 is closed to start the closing circuit of the normally open contact of the relay K1; the opening state of Q1 and Q2 is opposite. The circuit for driving Q1 and Q2 by the main control CPU is as follows: the output of the main control CPU is connected to the base of the transistor Q3 through the resistor R11, the emitter of the transistor Q3 is connected to the ground, and the base is connected to the ground through the resistor R9; the collector of Q3 is connected to the base of Q1 to realize the driving control of Q1; the output of the main control CPU is connected to the anode of the diode D7 through the capacitor C18, the cathode of the diode D7 is connected to the base of the transistor Q4 through the resistor R10, the emitter of the transistor Q4 is connected to the ground, and the collector is connected to the base of Q2 through the resistor R8, thereby realizing the driving control of Q2, and whether Q2 is started or not can realize the control of the on-off of the coil, and after the coil of the relay K1 is powered on, the normally open contact of the relay K1 is closed.

[0039] In the embodiment, the pre-driving circuit is used for driving the motor, and the pre-driving circuit comprises a gate driver and a bridge circuit composed of four MOSs; the main control unit CPU is connected to the gate of each MOS in the bridge circuit through the gate driver; the output end of the bridge circuit is connected to the steering motor. Figure 4 As shown in the pin and peripheral circuit diagram of the gate driver chip and the bridge circuit composed of four MOSs, the pre-driving circuit adopts the gate driver and four N-channel MOSFETs, the four N-channel MOSFETs form a bridge circuit for driving the steering motor; wherein the gate driver uses the DRV702Q chip, and the MOS adopts JMSL0402BGQ; the pre-driver and the MOSFET bear the main motor control, the pre-driver has strong protection function, including fault diagnosis and MCU watchdog, built-in dead time, MOSFET breakdown protection, MOSFET VDS overcurrent monitor, gate driver fault detection, and under-voltage and over-voltage protection.

[0040] The host CPU in the embodiment is connected to the vehicle controller of the vehicle through the CAN communication circuit, for receiving the control signal of the vehicle corner sent by the vehicle controller. The CAN communication circuit is integrated in the steering controller, for realizing the purpose of CAN communication. As shown in Figure 5 , the CAN communication loop adopts the standard CAN communication chip IC SIT1051T / 3 of the company Core Force. In order to cope with the growing demand of automobile CAN communication task, the CAN IC adopted in this scheme supports the CANFD function of 5M communication rate in the future. In order to ensure the quality of CAN communication signal, the voltage balance technology is adopted in this circuit to ensure the low communication error rate. As shown in Figure 5 , the pin and peripheral circuit diagram of the CAN chip SIT1051T / 3, wherein the TXD port and the RXD port are used for connecting to the host CPU; the CANH and the CANL are used for connecting to other vehicle controllers on the vehicle through the CAN signal.

[0041] The voltage and current / voltage sampling circuit is also integrated in the controller, which is used for collecting the current and voltage of the steering motor, and the output end is connected to the host CPU. The host CPU can monitor the control current and voltage of the steering motor, and can realize the protection and monitoring of overvoltage and overcurrent. At the same time, the controller of the application integrates a memory for storing various data, and the memory adopts EEPROM to realize more secure data storage.

[0042] The temperature monitoring circuit is integrated in the steering controller in the embodiment, which is used for detecting the temperature of the controller, and the output end is connected to the host CPU. As shown in Figure 7 , the temperature monitoring circuit adopts a thermistor to monitor the temperature change inside the controller, so as to achieve the temperature protection effect. The temperature monitoring and alarm and protection function can be realized by monitoring the temperature of the controller. As shown in Figure 7 , the +5V power supply output terminal from the DCDC is connected to the ground through the series connection of the resistor R74 and the thermistor RT1. The terminal between the thermistor RT1 and the resistor R74 is connected to the ground through the resistor R75, and the electric signal representing the temperature size is output and sent to the sampling port of the host CPU to collect this electric signal, which provides the data monitoring basis for the temperature monitoring and protection of the host CPU.

[0043] As shown in Figure 8As shown, a control method of a low-speed unmanned steering controller, comprising: a vehicle-mounted controller of a whole vehicle issuing a target steering angle instruction to the steering controller through a CAN BUS network, and the steering controller internally performing PID calculation, and realizing a target angle steering function through three-loop control of an angle position loop, a speed loop and a current loop, which is stable in action, high in control precision and fast in response speed, and the target steering angle requirement is met by PID loop control of vehicle speed, steering angle and motor current as input signals to realize adjustment output of an output PWM signal.

[0044] As Figure 9 The control principle of the controller for steering control speed is that the steering speed is actually an important prerequisite for affecting the safety of the steering angle, and when the vehicle speed is too fast and the steering speed is too fast, safety risks will also be caused, so the steering F / B speed control is set in the application, the steering speed, the vehicle speed and the target steering speed are input into the controller, the difference between the steering speed and the target steering speed is calculated and a proportion K is given to obtain the calculated control difference, then the steering speed proportion and the vehicle speed proportion corresponding to the steering speed and the vehicle speed are calculated as the adjustment proportion of the control difference, the control difference is multiplied by the steering speed proportion and the vehicle speed proportion to obtain the final adjustment control target and is converted into a corresponding PWM signal to control the speed of the steering motor, so that the vehicle speed and the steering speed are adjusted to the target steering speed, and the safety and reliability of the control steering speed are improved.

[0045] The embodiment also provides a method for improving the data safety of the controller and avoiding the loss of the steering angle data, comprising: after the controller is powered on, the value of Turns is read from the EEPROM, the value is used as the initial value of Turns to participate in the steering angle calculation, after the correct steering angle is calculated, the steering angle is sent to the whole vehicle controller through the CAN module, then the voltage of the IG signal is detected, once the voltage of the IG signal is detected to be less than 9V, the value of Turns is immediately stored in the EEPROM to prevent the loss of the steering angle turns after power failure. Turns is the number of turns of the main shaft of the steering system (EPS), and the value is stored in the EEPROM to ensure that the system knows the initial steering angle / turns after the next power-on.

[0046] Obviously, the specific implementation of the present application is not limited by the above-mentioned manner, and various non-essential improvements made by adopting the method concept and technical scheme of the present application are within the protection scope of the present application.

Claims

1. A low-speed unmanned driving steering controller, the controller comprising a main control unit (CPU) and a pre-drive circuit, wherein the output terminal of the main control unit (CPU) is connected to the pre-drive circuit for driving the steering motor via the pre-drive circuit; characterized in that: The controller also includes a magnetic induction angle chip. The sensor magnet corresponding to the magnetic induction angle chip is set on the motor output shaft. The magnetic induction angle chip obtains the angle signal by analyzing the sensor magnet signal, and its output terminal is connected to the main control unit CPU. The controller also includes a relay K1 and a pre-charging circuit. The battery BAT is connected to the pre-drive circuit via the relay to supply power to the pre-drive circuit. The output terminal of the main control unit CPU is connected to the control terminal of the relay K1 and the control terminal of the pre-charging circuit respectively. The pre-charging circuit includes a pre-charging resistor R1 and a transistor Q1. The battery BAT is led out to a drive power supply terminal through the normally open contact of the relay K1. The drive power supply terminal is used to connect to the power supply terminal of the pre-drive circuit. A terminal is led out between the battery BAT and the normally open contact of the relay K1 and connected to the anode of the diode D1. The cathode of the diode D1 is connected to one end of the pre-charging resistor R1 through the transistor. The other end of the resistor R1 is connected to the drive power supply terminal. The cathode lead of diode D1 is connected to one end of the coil of relay K1 via transistor Q2, and the other end of the coil of K1 is grounded; the output of the main control unit CPU is connected to the control terminals of transistors Q1 and Q2 respectively to control the conduction and disconnection of transistors Q1 and Q2.

2. The low-speed unmanned driving steering controller as described in claim 1, characterized in that: The magnetic induction angle chip is connected to the main control unit CPU through a main and backup transmission interface.

3. A low-speed unmanned driving steering controller as described in claim 1, characterized in that: The controller also includes a power supply circuit, the input of which is connected to the battery BAT; the output of which outputs DC power to power the controller; the power supply circuit has an enable terminal EN, which is configured to input an ignition signal.

4. A low-speed unmanned driving steering controller as described in any one of claims 1-3, characterized in that: The pre-drive circuit includes a gate driver and a bridge circuit composed of four MOS transistors; The main control unit CPU is connected to the gate of each MOS in the bridge circuit via a gate driver; the output of the bridge circuit is connected to the steering motor.

5. A low-speed unmanned driving steering controller as described in any one of claims 1-3, characterized in that: The controller also includes a CAN communication circuit, and the main control unit CPU is connected to the vehicle's on-board controller via the CAN communication circuit.

6. A low-speed unmanned driving steering controller as described in any one of claims 1-3, characterized in that: The controller also includes a temperature monitoring circuit and a voltage / current sampling circuit. The temperature monitoring circuit is used to detect the temperature of the controller, and its output is connected to the main control unit CPU. The voltage / current sampling circuit is used to collect the current and voltage of the steering motor, and its output is connected to the main control unit CPU.

7. A low-speed unmanned driving steering controller as described in any one of claims 1-3, characterized in that: The main control unit CPU is connected to a memory, which is an EEPROM.

8. A control method for a low-speed unmanned driving steering controller as described in any one of claims 1-7, characterized in that: The method includes: the vehicle sends a target steering angle command to the steering controller through the CAN BUS network, the internal software of the steering controller performs PID calculation, and realizes the PWM signal corresponding to the target angle through three-loop control calculation of angle position loop, speed loop and current loop and outputs control.

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