Steer-by-Wire Force Feedback Actuator Torque Replication
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Solution Overview
Problem
Steer-by-wire steering systems lack effective force feedback actuators that are compact, lightweight, and cost-efficient while providing a natural driving experience, as current actuators are large, heavy, and complex, leading to inadequate driver feedback in critical driving situations.
Innovation Solution
A method and system that utilize a control system to determine steering information, control steering and force feedback actuators to replicate steering torque, and output an overshoot signal when torque exceeds a threshold, using haptic, acoustic, or optical transmitters to alert the driver, allowing for a smaller, lighter force feedback actuator that still provides intuitive driving feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force feedback actuator is used to provide steering wheel torque in a steer-by-wire system, then the driver receives haptic feedback about the driving situation, but the actuator becomes large, heavy, and mechanically complex
Solution Approach 1:
The patent replaces the traditional mechanical force feedback actuator with an electrical system that uses steering torque sensors and a control unit to calculate and generate feedback torque values. This substitution eliminates complex mechanical components while achieving the same haptic feedback function through electrical signals and control algorithms.
Solution Approach 2:
The patent introduces a control unit as an intermediary that receives steering torque information from sensors, calculates the appropriate feedback torque based on driving conditions, and sends control signals to the actuator. This intermediary layer simplifies the overall system by centralizing the control logic and decoupling the sensing and actuation components.
2Reliability
If a force feedback actuator is used to provide steering wheel torque, then the driver experiences natural haptic feedback, but the actuator becomes expensive
Solution Approach 1:
The patent replaces expensive mechanical force feedback actuators with a combination of steering torque sensors and a control unit that calculates feedback torque electronically. This substitution significantly reduces manufacturing costs by using simpler, more cost-effective electrical components instead of complex mechanical actuation systems.
Solution Approach 2:
The patent uses sensors to detect actual steering torque and creates an electrical copy of this torque information, which is then processed by the control unit to generate feedback torque values. This copying approach allows the system to replicate the feel of mechanical feedback using inexpensive electrical signals rather than expensive mechanical components.
3Object-affected harmful factors
If the steering column is removed in a steer-by-wire system, then occupant protection is improved and design freedom increases, but the driver loses natural force feedback from steering torque
Solution Approach 1:
The patent implements a feedback system where steering torque sensors detect the driver's steering input, the control unit calculates the appropriate feedback torque based on driving conditions and vehicle state, and the system generates haptic feedback through the steering wheel. This closed-loop feedback mechanism restores the natural force feedback experience that was lost when the mechanical steering column was removed.
Solution Approach 2:
The patent substitutes the mechanical force feedback transmission through the steering column with an electrical feedback system using torque sensors and a control unit. This substitution maintains occupant protection benefits while restoring haptic feedback through electronic means rather than direct mechanical coupling.
Data Source
AI summary
A method for operating a steer-by-wire steering system of a motor vehicle is proposed. The steer-by-wire steering system includes a steering wheel, a force feedback actuator coupled to the steering wheel, a steering actuator coupled to a steerable wheel, and a control system. The method includes a) the determination of steering information while taking into account a steering wheel angle and/or a driver's steering torque applied to the steering wheel by the driver; b) controlling the steering actuator while taking into account the steering information to adjust a desired wheel steering angle of the steerable wheel; c) controlling the force feedback actuator for setting a steering wheel torque; and d) providing a threshold value associated with steering wheel torque and/or the wheel steering torque; e) generating a torque value representing or reproducing the steering wheel torque and/or the wheel steering torque; and f) outputting an overshoot signal if the torque value reaches the threshold value. A corresponding steer-by-wire steering system is also proposed.