Rear Wheel Kinematic Control Circuit Fault Handling
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Solution Overview
Problem
In vehicle kinematic control systems, a failure of the electric motor controlling the rear wheels' track can lead to unpredictable steering, distracting the driver and reducing confidence in vehicle handling, especially when the motor fails while the rear wheels are in an off-centre position.
Innovation Solution
A vehicle kinematic control circuit with a fault detection system that uses dual sets of phase windings and motor bridge drivers to detect faults and either clamp or damp the motor rotor's movement, ensuring the rear wheels remain stable and prevent unwanted steering, even if one set of phase windings or microcontroller fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single set of phase windings is used to control the rear wheels' track, then the device complexity is reduced, but the reliability deteriorates because a fault causes unpredictable steering and driver distraction
Solution Approach 1:
The motor control system is segmented into two independent sets of phase windings (first set and second set), each capable of independently controlling the motor. This segmentation allows the system to maintain reliability by switching to the non-faulty set when one set fails, while keeping each segment relatively simple in structure
Solution Approach 2:
The system prepares for potential failures by having redundant phase winding sets in place before faults occur. The control circuit is designed to detect faults and automatically switch to the non-faulty set, cushioning against the harmful effects of motor failures and preventing unpredictable steering behavior
2Ease of operation
If the motor fails while rear wheels are in an off-centre position, then the vehicle can still be driven, but the driver experiences distraction and reduced confidence due to unpredictable steering
Solution Approach 1:
The control circuit continuously monitors the status of phase windings and detects faults in real-time. When a fault is detected, the system provides feedback to switch to the non-faulty set of phase windings, ensuring continuous and predictable control of the rear wheels while maintaining vehicle drivability
Solution Approach 2:
The system converts the potential harm of motor failure into a beneficial outcome by using the redundant phase winding set to maintain predictable steering control. Instead of allowing unpredictable crabbing motion, the fault detection and switching mechanism ensures the vehicle remains controllable, turning a harmful situation into a manageable one
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides predictable steering kinematics and maintains vehicle stability by locking or damping the rear wheels' movement in case of a fault, preventing rapid uncontrolled changes and ensuring the vehicle can be driven safely, even if one set of phase windings or microcontroller fails.
Implementation Method 1
apply appropriate PWM modulated voltage waveforms to the set of phase windings connected to that bridge to drive the rotor of the motor
Implementation Method 2
an electric motor, the motor in use being connected mechanically to at least one rear wheel of the vehicle such that angular movement of the rotor of the motor causes an angular variation of the track of the rear wheel
Implementation Method 3
a fault detection circuit which monitors the operation of the at least one microcontroller, the motor bridge driver circuit, and the at least two sets of phase windings, thereby to detect a fault condition
Implementation Method 4
drive the rotor of the motor in a second, different manner... locking or damping the rear wheels' movement in case of a fault, preventing rapid uncontrolled changes
Data Source
AI summary
A vehicle kinematic control circuit for a vehicle adjusts the track of one or more rear wheels of the vehicle through a limited angular range, using an electric motor, connected mechanically to at least one rear wheel. The motor has at least two independently operable sets of phase windings, each set comprising at least two phase windings, each set connected to a motor bridge, controlled by a microcontroller. In normal use the microcontroller generates motor control signals that apply appropriate PWM modulated voltage waveforms to the set of phase windings connected to that bridge to drive the rotor of the motor in a first manner thereby to actively steer the rear wheel. A fault detection circuit monitors the operation of the one microcontroller, the motor bridge driver circuit, and the two sets of phase windings, to detect a fault condition, and in the event of a fault condition being detected causes one of the non-faulty motor bridges and an associated non-faulty set of phase windings to be operated to drive the rotor of the motor in a second, different manner.