Independent Wheel Torque Control for Low-Radius Vehicle Turning
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Solution Overview
Problem
Current vehicle speed control systems face challenges in managing wheel speed on uneven and varying friction surfaces, limiting the ability to perform turns on narrow roads and maintaining control on different terrain types.
Innovation Solution
A speed control system that independently controls each wheel's torque based on accelerator pedal input, surface friction, and sensor data, allowing for target wheel speeds to be maintained across multiple motors, enabling improved control on uneven and different friction surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gas pedal adjusts the output power of the engine to increase speed, then the wheel speed increases, but the wheel speed becomes variable and uncontrollable on different surface conditions due to wheel slip
Solution Approach 1:
The patent divides the wheel speed control into independent segments by controlling each wheel individually through separate motors. The system monitors wheel slip for each wheel independently and adjusts motor torque separately for each wheel, allowing precise control even on varying surface conditions. This segmentation enables the vehicle to maintain target wheel speeds despite differences in surface friction across different wheels.
Solution Approach 2:
The system implements continuous feedback by monitoring actual wheel speeds and comparing them to target speeds. Based on this feedback, the control system adjusts motor torque in real-time to compensate for wheel slip and maintain desired wheel speeds. The feedback mechanism includes detecting wheel slip conditions and using this information to modify motor output dynamically.
2Ease of operation
If the front wheels are turned to perform turns, then the vehicle can change direction, but the turning radius is limited by the maximum wheel turning degree
Solution Approach 1:
The patent applies asymmetric control by allowing different wheel speeds on opposite sides of the vehicle during turning maneuvers. By independently controlling the speed of each wheel, the system can create asymmetric speed distributions that enable tighter turning radii. The inner wheels can rotate slower or even reverse while outer wheels maintain forward motion, dramatically reducing the turning radius beyond what traditional steering alone can achieve.
Solution Approach 2:
The system dynamically adjusts wheel speeds during turning operations rather than relying on fixed steering geometry. The control system continuously modifies individual wheel speeds based on the turning phase and required radius, enabling adaptive turning performance. This dynamic control allows the vehicle to optimize turning radius in real-time based on operational conditions.
3Adaptability or versatility
If the vehicle operates on uneven and variable friction surfaces, then the vehicle can traverse different terrain, but the wheel speed control becomes difficult due to varying surface conditions
Solution Approach 1:
The system applies local quality control by independently adjusting the torque and speed control parameters for each wheel based on its specific surface conditions. Each wheel's motor controller operates independently, allowing the system to adapt to local variations in surface friction. If one wheel encounters a slippery surface while others are on firm ground, the control system compensates by adjusting only the affected wheel's torque to maintain overall vehicle performance.
Data Source
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AI summary
Systems and methods are provided herein for controlling the speed on each wheel of a vehicle, possibly operating a vehicle in a speed control mode. In response to receiving input to engage speed control mode and receiving an accelerator pedal input, the system determines a target wheel speed based on the accelerator pedal input, monitors wheel speed of each of a plurality of wheels and determines, for each monitored wheel, a difference based on the monitored wheel speed and the target wheel speed. A torque is provided to each of the plurality of wheels based on the respective difference to achieve the target wheel speed.