Pedal Drive Feedback Torque Control for Haptic Simulation
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Solution Overview
Problem
Series-type hybrid electric vehicles lack the expected mechanical interaction and feedback, leading to an unnatural feel and potentially dangerous pedal resistance torque, which can cause balance issues and reduced traction control, especially on uneven surfaces.
Innovation Solution
A pedal drive system with a control unit that provides controllable feedback torque, decoupling pedal drive from wheel drive, using a haptic renderer to simulate pedal reference trajectories and adapt inertia models for improved haptic feel and vehicle handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If series-type hybrid electric vehicle setup is used, then device complexity is reduced and manufacturing cost is lowered, but haptic feedback quality deteriorates and pedal feel becomes unnatural
Solution Approach 1:
The patent replaces the mechanical drivetrain connection with an electrical connection through a generator-motor system. The generator is coupled to the pedals and converts mechanical energy to electrical energy, which is then used by an electric motor to drive the wheels. This substitution eliminates complex mechanical transmissions while maintaining drivetrain functionality, though it initially creates the haptic feedback problem that the feedback torque control solution addresses.
Solution Approach 2:
The patent implements a feedback control system where a sensor measures the actual pedal rotation and the controller compares it to a reference trajectory. The controller then adjusts the feedback torque applied to the pedals to minimize deviations from the expected mechanical bicycle behavior. This closed-loop feedback restores natural pedal feel despite the electrical drivetrain substitution.
2Device complexity
If series-type hybrid electric vehicle setup is used, then mechanical transmission components are eliminated, but pedal resistance torque becomes insufficient and safety is compromised
Solution Approach 1:
The patent eliminates mechanical transmission components (chain, belt, gears) by replacing them with an electrical power transmission system. The generator converts pedal mechanical energy to electrical energy, which is then converted back to mechanical energy by the electric motor at the wheels. This substitution reduces mechanical complexity but creates the problem of insufficient pedal resistance torque that the feedback control solution resolves.
Solution Approach 2:
The patent dynamically adjusts the feedback torque parameter to ensure adequate pedal resistance. By controlling the generator's electromagnetic torque and adding artificial feedback torque through the control system, the patent maintains sufficient resistance torque at the pedals despite the absence of mechanical transmission components, thereby ensuring operator safety and stability.
3Ease of manufacture
If simplified electrical drivetrain is used, then manufacturing cost is reduced, but haptic feedback quality and ergonomics deteriorate
Solution Approach 1:
The patent replaces complex mechanical drivetrains with a simpler electrical system consisting of a generator, battery, and electric motor. This substitution significantly reduces manufacturing costs by eliminating expensive mechanical components like transmissions and gear shifts. The added feedback control system restores ergonomic pedal feel, making the simplified design both cost-effective and comfortable to operate.
Solution Approach 2:
The patent adds a feedback control layer to the simplified electrical drivetrain. Sensors monitor pedal position and rotation, and the controller adjusts generator torque and feedback forces to replicate the haptic characteristics of traditional mechanical bicycles. This feedback mechanism restores ergonomic quality without requiring complex mechanical components, achieving both cost reduction and ergonomic maintenance.
4Adaptability or versatility
If series-type hybrid electric vehicle is used, then vehicle flexibility is improved, but pedal response behavior becomes unexpected and control precision is reduced
Solution Approach 1:
The patent implements precise feedback control to maintain accurate pedal response behavior. The controller continuously monitors pedal position, velocity, and acceleration, comparing actual values against reference trajectories. By dynamically adjusting feedback torque based on these measurements, the system maintains precise pedal response characteristics even as the vehicle operates in flexible hybrid modes, ensuring predictable and accurate operator control.
Solution Approach 2:
The patent employs dynamic control strategies that adapt the feedback torque in real-time based on vehicle operating conditions. The system adjusts the characteristics of the simulated mechanical drivetrain response according to the vehicle's actual state, maintaining precise pedal response precision while allowing the vehicle to operate flexibly in different power modes (pedal-only, generator-assisted, motor-assisted, or battery-only operation).
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 system enhances haptic feedback and vehicle handling by simulating the inertia of a mechanical bicycle, providing a more ergonomic experience and improved stability and traction control.
Implementation Method 1
The provided input muscle power is converted into electric energy using a generator, which is mechanically coupled to the respective pedal, lever, or handle.
Implementation Method 2
The electric energy is then fed to an electric motor to drive the vehicle
Implementation Method 3
The control unit comprises a haptic renderer, configured for control of said feedback torque based on at least one pedal reference trajectory
Data Source
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AI summary
A pedal drive system (10), in particular for an electric vehicle or a training apparatus, and for generating electrical power from muscle power of a user with at least one pedal (11) and an electric generator (13), connected mechanically with said at least one pedal, is provided. To improve the haptic feel and feedback at the pedal, a control unit (30) is provided for controlling a feedback torque, applied at said pedal, wherein the control unit comprises a haptic renderer (31), configured for control of said feedback torque based on at least one predefined pedal reference trajectory.