Robot Teleoperation Haptics for Stable Force Feedback at Contact
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Solution Overview
Problem
Existing remote control systems struggle to properly implement force control and notify the operator when a robot encounters reactive forces outside a predetermined range or near the boundary, especially when a small contact force is applied, leading to instability and inadequate notification of contact occurrence.
Innovation Solution
A remote control system incorporating an operator, robot, haptic notifier, and controller that performs force control and notifies contact through a haptic interface, using vibration actuators to distinguishably convey contact forces within and outside a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force control is implemented for reactive forces within a predetermined range, then proper force control can be achieved for normal operations, but force control becomes unstable or unresponsive when reactive forces are outside the range or near the boundary
Solution Approach 1:
The notification threshold is dynamically adjusted based on the relationship between the reactive force magnitude and the notification threshold. When the reactive force is close to the threshold, the threshold is temporarily lowered to enable notification, and when the reactive force is significantly larger than the threshold, the threshold is raised to prevent unnecessary notifications. This dynamic adjustment allows the system to adapt to varying force conditions and maintain reliable notification across different operational ranges.
Solution Approach 2:
The system changes the notification threshold parameter based on the detected reactive force magnitude. By adjusting the threshold parameter dynamically according to the current force conditions, the system can properly notify contact occurrence across a wide range of reactive forces while maintaining stable force control within the predetermined range.
2Measurement precision
If the notification threshold is set low to detect small contact forces, then contact notification sensitivity improves, but false notifications increase due to noise or minor variations
Solution Approach 1:
The notification threshold is not fixed but dynamically adjusted based on the reactive force magnitude. When a small reactive force is detected, the threshold is temporarily lowered to enable detection, but when the reactive force is large, the threshold is raised to prevent false notifications. This dynamic behavior allows the system to maintain high detection sensitivity while avoiding false positives.
Solution Approach 2:
Different threshold levels are applied locally based on the current reactive force conditions. Instead of using a single global threshold, the system applies adaptive threshold values that are appropriate for the current force magnitude, enabling precise contact detection in low-force scenarios while maintaining notification accuracy in high-force scenarios.
3Loss of information
If a haptic notifier is added to notify contact occurrence, then contact notification capability is improved, but device complexity increases
Solution Approach 1:
The haptic notifier acts as an intermediary device that translates contact force information into tactile feedback for the operator. By introducing this intermediate notification mechanism, the system can convey contact occurrence information without requiring complex visual or auditory interfaces, thus improving notification capability while adding minimal complexity.
4Device complexity
If the notification threshold is fixed at a predetermined value, then control logic is simple, but proper notification cannot be achieved when reactive forces vary significantly
Solution Approach 1:
The notification threshold transitions from a fixed predetermined value to a dynamic value that adapts to the current reactive force magnitude. This dynamic adjustment enables the system to properly notify contact occurrence across significantly varying reactive forces while maintaining relatively simple control logic through automated threshold adaptation.
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
Enables stable and responsive force control between the operator and robot while accurately notifying the operator of contact occurrences, enhancing operational stability and responsiveness.
Implementation Method 1
a haptic notifier 8 that notifies occurrence of contact of the robot with an object to the operating person
Data Source
AI summary
A remote control system includes an operator to be operated by an operating person, a robot that moves according to operation on the operator, a haptic notifier that notifies occurrence of contact of the robot with an object to the operating person, and a controller that performs force control of moving the robot according to an operation force applied from the operating person to the operator and moving the operator according to a reactive force received by the robot from the outside and notification control of notifying the occurrence of the contact to the operating person via the haptic notifier if the robot contacts the object.