Robotic Arm Contact Sensing for Controlled Surgical Reaction
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Solution Overview
Problem
Robotic medical systems face challenges in safely managing contact forces and torques during surgery, leading to potential injuries and discomfort for patients and medical personnel, as existing systems lack effective detection and response mechanisms to prevent excessive contact forces and torques.
Innovation Solution
A robotic medical system equipped with sensors and processors that detect contact forces and torques on robotic arms, enabling controlled movements and null space motions based on the magnitude, direction, and rate of change of these forces and torques, and prioritizing tasks to optimize safety, power consumption, and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the robotic arm is designed with high stiffness and precision control to maintain pose accuracy, then manufacturing precision and control accuracy are improved, but the risk of excessive contact force causing injury to patient or personnel increases
Solution Approach 1:
The robotic arm transitions from a static rigid structure to a dynamic system with compliant elements. Sensors detect contact forces and torques in real-time, and the control system dynamically adjusts joint movements to reduce contact forces while maintaining cannula pose accuracy within acceptable tolerances.
Solution Approach 2:
Force sensors and torque sensors are integrated into the robotic arm to provide real-time feedback on contact forces. This feedback loop enables the control system to detect excessive contact forces and immediately adjust the robotic arm's movement to prevent injury to the patient or medical personnel.
2Manufacturing precision
If the robotic arm executes null space motion to maintain pose during contact, then pose accuracy is maintained, but the operational complexity and risk of additional collisions increase
Solution Approach 1:
The robotic arm autonomously detects contact forces through integrated sensors and automatically executes appropriate responses without requiring operator intervention. The system self-adjusts by moving joints in null space or reducing velocity based on detected contact characteristics, maintaining pose accuracy while simplifying operator workload.
Solution Approach 2:
The control system is pre-programmed with multiple response strategies (null space motion, velocity reduction, task prioritization) that are automatically selected based on the characteristics of detected contact forces. This preliminary preparation of response options reduces the complexity of real-time decision-making during surgery.
3Object-affected harmful factors
If the operator manually moves the robotic arm out of contact, then contact force is reduced, but surgical interruption and loss of time occur
Solution Approach 1:
The robotic arm autonomously detects and responds to contact forces without requiring operator intervention. The system automatically executes null space motion or velocity reduction to eliminate excessive contact forces, maintaining surgical continuity and preventing time loss associated with manual repositioning.
Solution Approach 2:
The robotic arm maintains continuous surgical operation by automatically responding to contact forces. The seamless integration of force detection and autonomous response mechanisms ensures that surgical procedures continue without interruption, preserving the efficiency and flow of the surgical workflow.
4Measurement precision
If sensors are distributed throughout the robotic arm to detect contact forces, then detection precision is improved, but device complexity and cost increase
Solution Approach 1:
The robotic arm is divided into multiple segments with sensors strategically placed at key locations (joints, links, end effector). Each sensor detects local contact forces and torques, and the control system integrates this distributed information to achieve comprehensive contact detection with improved precision while managing system complexity.
Data Source
AI summary
Robotic medical systems can be capable of contact sensing and contact reaction. A robotic medical system can include a robotic arm and one or more sensors. The robotic medical system can be configured to detect, via the one or more sensors, a contact force or torque that is exerted on the robotic arm by an external object. In response to detecting the contact force or torque, and in accordance with a determination that a magnitude of the contact force or torque is between a lower contact force or torque limit and an upper contact force or torque limit, the robotic medical system can enable a first set of controlled movements on the robotic arm in accordance with the detected contact force or torque.