Continuus carbon fiber beams which generate support and allow for a large range of motion are used as a back interface. Combined with the torque source at the hip, they generate the torque which reduces the strain on the lower back.
We assessed full body kinematics and spine load components in natural lifting, to find kinematic and support pattern requirements for the SPEXOR actuated exoskeleton. Furthermore, using a benchmark actuated exoskeleton, we investigated how specific actuation control modes interact with subject behavior, and how this affects spine loading.
We assessed to what extent a benchmark exoskeleton reduces spine loading and changes body kinematics during static trunk bending and during lifting. Additionally, we investigated how it affects perceived comfort, effort, performance, and metabolic energy consumption during functional activities such as walking and stair climbing. Based on these data, biomechanical requirements for the spexor passive exoskeleton were refined.
The SPEXOR monitoring system is now linked with the full-body dynamical model providing insight into the musculoskeletal stress parameters. Further optimization for real-time processing and feedback are being addressed.
The controller for engagement and disengagement of the hip spring is developed. It is based on the probabilistic model of the human motion that classifies whether the user requires the support of the exoskeleton or the exoskeleton should remain disengaged to allow free motion.
We evaluated our optimized stress monitoring system, consisting of pressure insoles and inertial sensors, by comparing its performance to a laboratory grade system in a mock-up of realistic working conditions. Sensor outcomes and resultant low back load measures were compared between systems. The system was found to meet standards in accordance with the previously defined requirements.
In recent work UHEI led efforts towards the modeling of a passive spinal exoskeleton, and simulating the interaction between the human user and the exoskeleton (Millard et al. 2017, Manns et al. 2017, Harant et al. 2017). These results build upon earlier contributions of a dynamic whole body human model which is used as a basis for the exoskeleton design. We use a combined model of a human and a parametrized exoskeleton and setup optimal control problems to identify exoskeleton spring characteristics or motor torques for lifting motions. The motions simulated are either fitted to recorded data (collaboration with S2P and VUA), or generated as the solution of a minimization function. We also compute the forces and torques transmitted between the human and the exoskeleton. These are important first measures that will help support the exoskeleton and human-exoskeleton-interface design process.
Ready for use, OBG accomplished the first functional prototype of the musculoskeletal stress monitoring system. Looking forward for research, implementation and validation of the SPEXOR biomechanical models with the prototype.
We defined the required biomechanical output variables and their accuracy for the sensory feedback system. In addition, we identified the set of sensors that best fits this requirement while optimizing feasibility under realistic working conditions.
In December 2016 we formalized the conceptual design based on the specifications from the requirements workshop. Over the last months, OBG and VUA had an intensive exchange about the used biomechanical models to consider the latest scientific approaches for the monitoring system. We now started with the implementation of the monitoring system.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 687662.