Force Feedback Control for Motion Simulator Haptic Synchronization
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Solution Overview
Problem
Existing motion simulators based on Stewart's platform are expensive and do not effectively control the user's experience of motion, as they primarily target the vestibular system, whereas force feedback devices only address the kinaesthetic sense, lacking synchronization in haptic effects.
Innovation Solution
A method and device for controlling force-feedback devices to manage user experience by adjusting displacement parameters, such as initial and final coordinates, speed, and acceleration, using a biomechanical model and inverse kinematics to ensure perceived motion aligns with visual content, incorporating a washout filter to optimize user experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motion simulators based on Stewart's platform are used to generate motion sensations, then the user's vestibular system is effectively stimulated, but the cost of the system becomes very high
Solution Approach 1:
The patent replaces the complex mechanical Stewart platform system with a software-based control system that uses inverse kinematics and biomechanical models to generate haptic effects. This substitution of mechanical complexity with computational algorithms significantly reduces hardware costs while maintaining motion sensation effectiveness through force feedback devices.
Solution Approach 2:
The patent creates a virtual model of the user's biomechanical system and uses inverse kinematics to calculate equivalent motion effects. By copying and simulating the complex mechanical relationships through software models rather than physical hardware, the system achieves motion simulation effects at lower cost.
2Ease of manufacture
If force feedback devices are used to address the kinaesthetic sense, then the system cost is reduced, but the control methods for Stewart's platform are not adapted for these devices
Solution Approach 1:
The patent transforms the control approach by changing the fundamental parameters from platform displacement control to force feedback device control. It uses inverse kinematics to map desired motion effects into appropriate force feedback parameters (magnitude, direction, timing), creating a new control paradigm adapted specifically for force feedback devices rather than mechanical platforms.
Solution Approach 2:
The patent creates a universal control framework based on inverse kinematics and biomechanical modeling that can be applied to various force feedback device configurations. This framework provides adaptability across different device types while maintaining consistent haptic effect generation, making the system versatile rather than device-specific.
3Reliability
If displacement parameters of force feedback devices are adjusted to enhance perceived motion, then user experience is improved, but synchronization with visual content becomes complex
Solution Approach 1:
The patent performs preliminary calculations using inverse kinematics and biomechanical models to pre-determine the appropriate displacement parameters for force feedback devices based on the desired haptic effect and visual content characteristics. By calculating and preparing synchronization parameters in advance rather than reacting in real-time, the system achieves precise synchronization without complex real-time coordination.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the actual displacement and force applied by the devices, comparing it against the target parameters derived from inverse kinematics calculations. This feedback loop allows for real-time adjustments to maintain synchronization with visual content while managing complexity through closed-loop control.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The invention relates to a method for controlling at least one force-feedback device (101, 102, 103) associated with at least a part of the body of a user (11). As to control the user's experience of motion and movements induced by the displacement(s) of the force feedback device(s) (101, 102, 103), the method comprises the steps of: - determining a speed value of a movement of the at least a part of the body according to at least a parameter representative of the displacement of the at least one force-feedback device (101, 102, 103), the movement of the at least a part of the body being induced by the displacement of the at least one force-feedback device (101,102, 103); - comparing the determined speed value with a threshold speed value as to determine whether the displacement of the at least one force-feedback device (101, 102, 103) is perceived by the user (11); - controlling the at least one parameter according to the comparison result. The invention is also related to a device and computer program product implementing the method