Robotic Upper Trunk Support With Variable Stiffness Control

The patent implements a variable stiffness actuator that dynamically adjusts the support stiffness based on patient muscle strength and training phase. The actuator transitions between rigid and compliant states, allowing the system to maintain structural stability when needed while adapting to patient movement requirements. This is achieved through real-time control of the actuator's stiffness parameter, enabling the robotic device to behave as a rigid support structure during stable phases and as a compliant partner during movement phases.

The system changes the physical parameter of stiffness in the actuator to resolve the contradiction. By varying the stiffness parameter according to patient conditions and training objectives, the system achieves both structural stability and movement compliance. The stiffness parameter is adjusted based on feedback from sensors measuring patient muscle strength and movement characteristics, allowing the device to adapt its mechanical properties in real-time.

The patent employs feedback control where sensors continuously measure patient muscle strength, movement velocity, and position. This information is fed back to the controller, which adjusts the actuator output force in real-time to maintain accurate support. The feedback loop enables precise force control without requiring overly complex mechanical mechanisms, as the accuracy is achieved through intelligent control rather than mechanical complexity.

The variable stiffness actuator incorporates integrated sensors and control electronics that enable it to autonomously adjust its behavior based on patient conditions. The actuator essentially serves itself by using its own sensor data to regulate its output, reducing the need for external complex control systems while maintaining high force accuracy.

The patent applies partial action by providing just enough support force to ensure patient safety without fully bearing the patient's weight. The variable stiffness actuator dynamically adjusts the support level, providing high force when safety is at risk but reducing force to allow patient effort during appropriate training phases. This partial support approach maintains safety while preserving training effectiveness by requiring appropriate patient engagement.

The system dynamically adjusts the support force level based on real-time assessment of patient capability and training objectives. During phases where patient effort is desired, the actuator reduces support force to challenge the patient. During phases where safety is paramount or patient fatigue is detected, the actuator increases support force. This dynamic adjustment resolves the contradiction between safety and training effectiveness.