Surgical Robot Master Handle Force Feedback via Motion Estimation
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Solution Overview
Problem
In minimally invasive surgery using surgical robots, there is a lack of effective feedback of external forces applied to surgical tools to the operator, which hampers the operator's ability to sense the resistance and texture of tissues during remote-controlled procedures without the use of sensors.
Innovation Solution
A surgical robot system and control method that estimates external forces applied to surgical tools by detecting the movement of the master device and feeds this information back to the operator, using a master external force estimation unit, force compensation unit, and joint motion control to simulate the forces, allowing the operator to feel the resistance through handle movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force sensors are installed on surgical tools to provide tactile feedback to the operator, then the operator can sense external forces applied to surgical tools, but the device complexity and cost increase significantly
Solution Approach 1:
The patent introduces an intermediary computational model that mediates between the master device movement and force feedback generation. Instead of directly measuring force with sensors, the system uses a dynamic model of the surgical tool and tissue interaction to compute equivalent force signals from position and velocity data, thereby avoiding direct force sensing while achieving tactile feedback
Solution Approach 2:
The patent replaces the mechanical force sensing system with a computational mechanics model. The physical force measurement mechanism is substituted by mathematical models that calculate force based on observed motion parameters, eliminating the need for physical force sensors while maintaining the functional equivalent of force feedback
2Measurement precision
If force sensors are installed on surgical tools to measure external forces, then accurate force measurement is achieved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The patent creates a computational copy or model of the physical force interaction. Instead of measuring the actual physical force directly, the system generates a virtual copy of the force signal through mathematical modeling based on observed motion parameters, achieving measurement precision without the complexity of physical sensing hardware
Solution Approach 2:
The patent substitutes the mechanical force measurement system with a computational approach. The physical force sensing mechanism is replaced by mathematical models that replicate force measurement functionality through position and velocity data processing, simplifying manufacturing while maintaining measurement capability
3Ease of operation
If the master device is remotely controlled without force feedback, then the operator has simplified control, but the operator cannot sense the resistance and texture of tissues during surgery
Solution Approach 1:
The patent implements a feedback mechanism that generates virtual force signals based on the computational model and feeds them back to the master device. This feedback loop provides the operator with tactile information about tissue resistance and texture without complicating the control interface, as the force feedback is generated computationally rather than through physical sensing
Solution Approach 2:
The patent introduces a computational intermediary that translates simple position control signals into rich tactile feedback information. The intermediary model processes basic motion data and generates equivalent force signals, thereby recovering lost tactile information without adding physical sensing complexity to the control system
Data Source
AI summary
A surgical robot system may include a slave device provided with surgical tools and a master device remotely controlling motion of the surgical tools. The master device may include handles controlling the motion of the surgical tools, a master external force estimator estimating external force applied to the handles, a force compensator generating a first force control signal to cancel out the estimated external force, and a master controller moving and rotating respective joints of the handles in such a way that the external force applied to the handles is canceled out using the generated force control signal.