Cooperative compliant traction mechanism for human-friendly biomechanical energy harvesting

•The concept of human-friendly biomechanical energy harvesting is proposed.•A cooperative compliant traction mechanism is designed to reduce the impact on users.•The mechanical modulation mechanisms are used to improve the performance.•A user wearing the prototype can easily generate an average power of 0.22 W.•The possibility of self-powered human-assisted system is demonstrated.