A method to model anticipatory postural control in driver braking events

Abstract

Human body models (HBMs) for vehicle occupant simulations have recently been extended with active muscles and postural control strategies. Feedback control has been used to model occupant responses to autonomous braking interventions. However, driver postural responses during driver initiated braking differ greatly from autonomous braking. In the present study, an anticipatory postural response was hypothesized, modelled in a whole-body HBM with feedback controlled muscles, and validated using existing volunteer data. The anticipatory response was modelled as a time dependent change in the reference value for the feedback controllers, which generates correcting moments to counteract the braking deceleration. The results showed that, in 11 m/s(2) driver braking simulations, including the anticipatory postural response reduced the peak forward displacement of the head by 100mm, of the shoulder by 30 mm, while the peak head flexion rotation was reduced by 18°. The HBM kinematic response was within a one standard deviation corridor of corresponding test data from volunteers performing maximum braking. It was concluded that the hypothesized anticipatory responses can be modelled by changing the reference positions of the individual joint feedback controllers that regulate muscle activation levels. The addition of anticipatory postural control muscle activations appears to explain the difference in occupant kinematics between driver and autonomous braking. This method of modelling postural reactions can be applied to the simulation of other driver voluntary actions, such as emergency avoidance by steering.

Neck postural stabilization, motion comfort, and impact simulation

“…In erect postures, lumbar stabilization determines trunk motion and thereby affects headeneck stabilization. Full-body human models including multisegment models of the complete spine have been developed and validated for impact loading (Happee, Hoofman, van den Kroonenberg, Morsink, & Wismans, 1998;Happee, Verver, & de Lange, 2000;Meijer et al, 2013;Östh, Brolin, & Bråse, 2015;Östh, Eliasson, Happee, & Brolin, 2014;Östh, Mendoza-Vazquez, Svensson, Linder, & Brolin, 2016). Such models have also been validated for vertical vibration transmission on rigid and compliant seats (Happee et al, 2000;Verver, FIGURE 19.10 NBDL volunteer test configuration, instrumentation (left), posture at pulse onset (mid), and posture at maximum head rotation with 15G loading (right).…”

Estimating the Effects of Awareness on Neck-Muscle Loading in Frontal Impacts with EMG and MC Sensors

“…The reflex activation due to a threat results in a startled response, characterised by rapid muscle co-contraction of the agonist and antagonist muscles, effectively stiffening the joints of the human body [ 1 , 4 , 5 , 6 , 7 ]. The voluntary activation is initiated by the occupant to adjust the posture or to brace in a critical situation [ 8 , 9 , 10 ]. Studies with volunteers subjected to conditions of low-severity frontal impacts, vehicle braking or lane-change manoeuvres observed smaller displacements of the upper body and a shorter onset of the neck-muscle activity when the volunteers were braced [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”

“…Several methods of muscle control are used in active human-body modelling, like predefined muscle-activation curves and closed-loop control for stabilising posture or executing dynamic tasks [ 3 , 22 ]. Östh et al [ 10 , 23 ] developed a whole-body human-body model (HBM) with feedback-controlled muscles for vehicle-braking simulations, noting that muscle-load sharing and muscle-recruitment patterns are two of the major challenges in developing closed-loop-controlled human-body models. Furthermore, the combination of feedback control for maintaining an initial posture, anticipatory control in a feedforward manner, and a reflex response in critical traffic situations need to be considered.…”

“…Analysing the startle response is necessary for any assessment of the injury risk to drivers and occupants, particularly in vehicles with autonomous-manoeuvring capabilities required by legislation. The transition between the startle response and voluntary action needs to be investigated further to support the development of vehicle restraints and active safety systems [ 10 , 24 , 25 ]. Hence, there is an increasing need to study the human-body active response in autonomous-vehicle manoeuvres and low-severity impacts, where timing and the pattern of muscle activation play a crucial role.…”

Amplitude Analysis of Lower Leg Muscle in Car Pedal Operation in Specific Driving Posture and Duration

“…As for example, four articles investigated a driver's behavior and performance when involving in pre-crash. [5][6][7][8]. Hault-Dubrelle et al and Behr et al for example, investigated the braking control system while operating the car [5][6].…”