Robotic Arm Motion Control via End Effector Force Sensing
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Solution Overview
Problem
Robotic surgery systems lack the intuitive control and sensitivity to effectively navigate and interact with tissues due to the lack of force feedback, making it difficult for surgeons to accurately manipulate surgical instruments, especially through small incisions and endoscopic procedures.
Innovation Solution
A robotic surgical system equipped with a control system that senses forces applied to the end effector and adjusts the movement parameters of the robotic arm, such as velocity and direction, based on these sensed forces, using sensors like piezo stacks and strain gauges to enhance dexterity and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional minimally invasive surgical instruments are used, then small incisions and reduced scarring are achieved, but the surgeon loses flexibility in tool placement and tactile feedback
Solution Approach 1:
The patent implements force sensing capability in the robotic surgical instrument that detects forces applied to the end effector and provides real-time feedback to the control system. This allows the surgeon to perceive tactile information about tissue interaction despite using minimally invasive instruments, resolving the contradiction between reduced scarring and loss of tactile feedback.
Solution Approach 2:
The patent introduces a robotic arm as an intermediary between the surgeon's control inputs and the surgical instrument. The robotic arm transmits force information from the tissue to the surgeon through controlled motion resistance, serving as a mediator that bridges the tactile feedback gap created by minimally invasive instrumentation.
2Manufacturing precision
If robotic surgery systems are used, then surgical precision is improved, but intuitive control and force sensitivity are reduced
Solution Approach 1:
The control system monitors forces applied to the end effector in real-time and uses this feedback to adjust robotic arm motion characteristics. This closed-loop feedback mechanism maintains surgical precision while restoring intuitive control by allowing the surgeon to sense tissue forces through the robotic system's resistance characteristics.
Solution Approach 2:
The patent dynamically adjusts the robotic arm's motion parameters based on sensed forces. The system modifies velocity, acceleration, and positioning characteristics in real-time according to tissue interaction forces, maintaining precision while adapting to provide intuitive control that responds naturally to surgeon inputs and tissue resistance.
3Measurement precision
If force sensing is added to the robotic system, then tissue interaction control is improved, but system complexity increases
Solution Approach 1:
The robotic arm components serve multiple functions: they provide surgical precision, transmit forces from tissue to the control system, and deliver controlled motion to the end effector. By making the existing robotic components multi-functional, the system achieves force sensing capability without proportionally increasing overall system complexity.
Solution Approach 2:
The patent combines force sensing capability with the existing robotic arm structure. The force sensors are integrated into the robotic arm's mechanical components, merging the sensing function with the actuation and positioning functions already present in the system, thereby reducing the incremental complexity of adding force measurement capability.
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 improves the surgeon's ability to perform precise surgical tasks by providing real-time force feedback, allowing for more intuitive and accurate control of the robotic arm, reducing the risk of tissue damage and shortening procedure times.
Implementation Method 1
The sensor assembly can include one or more of a piezo stack and a strain gauge that senses a resistance load
Implementation Method 2
The sensor assembly can include one or more of a piezo stack and a strain gauge that senses a resistance load
Data Source
AI summary
A robotic surgical system including a control system that controls the movement of a robotic arm is described. The robotic arm can be coupled to a tool assembly that includes an end effector positioned at a distal end of a shaft. The control system can assist with controlling the movement of the end effector and any tooling (e.g., cutting tool, boring tool, jaws, etc.) associated with the end effector, such as for either cutting through tissue or controlling a tension in the tissue. The tool assembly can include one or more sensors that measure a variety of forces or velocities associated with either the robotic arm or end effector. The control system can collect and monitor such sensed forces and velocities to determine and control one or more appropriate movement parameters associated with the robotic arm thereby controlling the cutting of tissue and preventing unwanted cutting of tissue. Furthermore, movement parameters associated with more than one robotic arm can be controlled by the control system.