Page 115 - Handbook of Biomechatronics

Model-Based Control of Biomechatronic Systems 111

Fig. 6 (A) High-fidelity integrated driver-vehicle model and (B) variation of the shoulder
and elbow angles and the rotation of the humerus about the vertical axis for a sinusoidal
steering wheel angle. The presented angles are consistent with the definitions rec-
ommended by the International Society of Biomechanics (ISB) (Wu et al., 2005).

during steering experiments (Mehrabi and McPhee, 2014b). In the first
experiment, the driver was instructed to hold the steering wheel stationary
against external torques (indicative of on-center steering); in the second
experiment, a sinusoidal steering maneuver was performed to simulate a sla-
lom maneuver (Hayama et al., 2012). Since real-life steering usually is a
combination of these two tasks, this driver model can realistically predict
muscle activities during everyday steering maneuvers.
The DAEs used to describe the high-fidelity integrated driver-vehicle
model are very complex and computationally expensive, and thus not suit-
able to be used within a real-time optimal control. Therefore, a simplified
version of this model that conveys the important dynamics of the system has
been developed.

3.2.2 Simplified Driver-Vehicle Model
The simplified integrated driver-vehicle model consists of a linear vehicle
model with a column-assist EPS system and a two-dimensional (2D) neu-
romuscular driver model. To develop the simplified driver model, we first
studied the kinematics of the high-fidelity 3D driver model performing a
sinusoidal steering maneuver. The modeled driver is holding the steering
wheel at the 3 and 9 o’clock positions as suggested by Hayama et al.
(2012), and the steering axis is parallel to the line connecting the shoulder
to the steering wheel as shown in Fig. 7A. The suggested driver’s posture
can be changed without substantially affecting the method and simulation