Neuromuscular dynamics in the driver–vehicle system

The work described in this article is part of a larger programme of research to understand the dynamic interaction between driver and vehicle. The driver’s neuromuscular dynamics are thought to be an important aspect of the interaction. Measurements of muscle activation voltage (electromyography, EMG) are used to identify the muscles involved in generating torque at the steering wheel. The EMG instrumentation is then developed to measure muscle co-contraction. In a lane-change manoeuvre performed on a driving simulator, muscle co-contraction is observed to occur during the manoeuvre. A mathematical model of the driver’s muscle reflex system suggests that co-contraction may be an optimal control strategy despite the extra energy required. The co-contraction increases the limb stiffness and thus the bandwidth of the control loop, which in turn allows smaller path-following errors.