Electric Vehicle Lean Stabilization via Differential Motor Current Control
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Solution Overview
Problem
Conventional electric vehicles with dedicated actuators for leaning suffer from increased size, weight, and complexity, making them less efficient and more cumbersome.
Innovation Solution
An electric vehicle design featuring a non-drive wheel, a pair of separately mounted drive wheels with vertically movable support mechanisms and motors, and a controller that adjusts motor currents to stabilize lean angles without a dedicated actuator, allowing for precise control of drive torque and lean angle stabilization through differential motor current management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated actuator device is provided for leaning the vehicle body, then the lean angle can be stabilized, but the vehicle becomes large, heavy, and complicated in construction
Solution Approach 1:
The patent merges the leaning function with the drive mechanism by using the drive wheels and their motors to achieve both propulsion and leaning control. The link mechanism connects the drive wheels to the vehicle body, allowing the drive system to simultaneously perform driving and leaning functions, thereby eliminating the need for a separate dedicated actuator device.
Solution Approach 2:
The drive wheels and motors are designed to serve multiple functions: they provide both the driving force for vehicle movement and the mechanism for leaning control. By making the drive system universal, the patent eliminates redundant components and simplifies the overall vehicle construction while maintaining lean angle stabilization capability.
2Reliability
If a dedicated actuator device is provided for leaning the vehicle body, then the lean angle can be stabilized, but the vehicle becomes heavy
Solution Approach 1:
The patent combines the leaning mechanism with the existing drive system, using the same link mechanism and drive wheels to achieve both propulsion and leaning. This merging eliminates the need for additional heavy actuator components, thereby reducing overall vehicle weight while maintaining lean angle stabilization.
Solution Approach 2:
By designing the drive system to perform both driving and leaning functions universally, the patent avoids adding separate heavy actuator devices. The multi-functional drive mechanism reduces vehicle weight compared to a system with dedicated leaning actuators.
3Reliability
If a dedicated actuator device is provided for leaning the vehicle body, then the lean angle can be stabilized, but the vehicle construction becomes complicated
Solution Approach 1:
The patent merges the leaning control function into the drive system by using the link mechanism that already connects the drive wheels to the vehicle body. This integration eliminates the need for separate actuator devices and their associated control systems, thereby simplifying vehicle construction while maintaining lean angle stabilization.
Solution Approach 2:
The drive system is designed to universally handle both propulsion and leaning control functions. By making the drive mechanism multi-functional, the patent reduces construction complexity compared to a system with dedicated separate actuators for leaning.
4Ease of operation
If the pair of drive wheels are driven with the same motor current, then the vehicle is simple to control, but the lean angle becomes unstable due to minute variations in rider position or handle operation
Solution Approach 1:
The patent implements feedback control by detecting the lean angle and adjusting the motor currents accordingly. The controller varies the motor currents based on the detected lean angle to actively stabilize the vehicle body, counteracting disturbances from rider movement or handle operations while maintaining simple operation.
Solution Approach 2:
The patent changes the motor current parameters dynamically based on lean angle conditions. By varying the motor currents in response to lean angle detections, the system achieves stable lean angle control without complicating the overall operation, as the current adjustment is automated through the control system.
Data Source
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AI summary
An electric vehicle includes a non-drive wheel, a pair of right and left drive wheels 35R and 35L provided separately from the non-drive wheel, a support mechanism for supporting the pair of drive wheels to be vertically movable, a pair of motors 33R and 33L corresponding to the pair of drive wheels, respectively, and a controller 81 for varying a difference between motor currents IMR and IML led to the pair of motors 33R and 33L, respectively. With this construction, the controller 81 varies an output difference between the motors 33R and 33L, thereby to be able to rotate each of the wheels 35R and 35L with appropriate torque. Therefore, even when the vehicle body is leaned, a lean angle of the vehicle body can be stabilized.