1、 外文翻译 共 19 页第 1 页 装 订 线 Driver perception of steering feel Abstract: Steering feel is optimized at a late stage of vehicle development, using prototype vehicles and expert opinion. An understanding of human perception may assist the development of a good feel earlier in the design process. Three psy
2、chophysical experiments have been conducted to advance understanding of factors contributing to the feel of steering systems. The first experiment, which investigated the frames of reference for describing the feel (tic properties) of a steering wheel, indicated that subjects focused on the steady s
3、tate force that they applied to the wheel rather than the steady state torque, and on the angle that they turned the wheel rather than the displacement of their hands. In a second experiment thresholds for detecting changes in both steady state steering-wheel force and steady state steering-wheel an
4、gle were determined as about 15 per cent. The rate of growth in the perception of steady state steeringwheel force and steady state steering-wheel angle were determined using magnitude estimation and magnitude production. It was found that, according to Stevens power law, the sensation of steady sta
5、te steeringwheel force increases with a power of 1.39 with increased force, whereas the perception of steady state steeringwheel angle increases with a power of 0.93 with increased steeringwheel angle. The implications for steering systems are discussed steering feel, proprioceptive, haptic feedback
6、 INTRODUCTION Driving a car is a complex task and involves many interactions between the driver and the vehicle through the various controls. Good performance of the system depends on how well a car 1 s able to create the drivers tensions, and how well differ- ences between those in-u-ns and the veh
7、iclesresponse can be detected the driver. The steering system is one of the primary controls in a car, allowing the driver to control the direction of the vehicle. The steering system not only allows the driver to control the car but also provides the driver with feedback through haptic (i.e. touch)
8、 senses, giving cues to the state of the road-tyre interface Forces originating at the road tyre interface (and related to the road wheel angle, vehicle red, and road adhesion), present themselves at the steering wheel (subject to kinematic losses through the steer-ing system, and subject to various
9、 assist methods in steering systems, e.g. hydraulic and electric power assist) where the driver can interact with them and develop an internal model of the steering propertiesand the environment The relationship between the steering-wheel torque and the steering-wheel angle has been considered a use
10、ful means of describing steering feel Various metrics of the relationship are used to define steering feel, and experiments have found that changing the relation between the steering-wheel force and steering-wheel angle can alter the driving experience. Knowledge of the way in which haptic stimuli a
11、t the steering wheel are 外文翻译 共 19 页第 2 页 装 订 线 perceived by drivers may therefore assist the development of steering-system designs. The perception of stiffness and the perception of viscosity seem to come from force, position, and velocity cues. Psychophysiological studies indicate that muscle spi
12、ndle receptors, cutaneous mechano-receptors, and joint receptors provide the neural.inputs used in the perception of the movement and force applied by a limb Psychophysics provides techniques to describe how subjects perceive stimuli. Classic measures include the difference threshold (the minimum ch
13、ange needed to detect a change in a stimulus) and the psychophystcal function (the relationship between changes in stimulus magnitude and the perception of those changes). However, the first step in quanti-fying steering feel using psychophysical methods is to identify what aspects of the haptic fee
14、dback at the steering wheel are used by drivers. Steering torque and steering angle describe the steady state characteristics of steering systems and their relationships have been identified as influencing steering feel. It seems appropriate to check whether subjects are judging what the experimente
15、r 15 measuring. It has not been shown whether the properties of steering system should be described in rotational frames of reference or translation frames of reference This paper describes three experiments designed to study how drivers perceive the steady state properties of steering wheels. The f
16、irst experiment investigated whether rotational or translation frames of reference are more intuitive to subjects. It was hypothesized that, if asked to match different steering-wheel sizes, either the rotational or the translation frame of reference would be matched more consistently. The second ex
17、periment deter- mined difference thresholds for the perception of steering-wheel force and angle, with the hypothesis that Webers law would apply for both stimuli. The third experiment investigated the psychophysical scales for the perception of the physical properties at steering wheels determining
18、 relationships between steering-wheel force and the perception of steering-wheel force, and between steering-wheel angle and the perception of steering-wheel angle. It was hypothesized that Stevens power law provides an adequate model for describing the psychophysical scales 2 APPARATUS A rig was bu
19、ilt to simulate the driving position of a 2002 model year Jaguar S-type saloon car as shown. The framework provided a heel point for subjects and supported a car seat and steering column assembly. The cross-section of a Jaguar S-type steering wheel was used to create the grips of the experimental st
20、eering wheel, which was formed by a rapid prototype polymer finished with production quality leather glued and stitched on to the subject posture was constrained the seat steering wheel, and heel point. The joint angle at the elbowmonitored and adjusted to 1100 for all subjects to ensure that they d
21、id not sit too close or too far from the steering wheel. The steering-column assembly included an optical incremental encoder to measure angle 外文翻译 共 19 页第 3 页 装 订 线 (resolution, 0.0440), a strain gauge torque transducer to measure torque (0.01 N accuracy), bearings to allow the wheel to rotate free
22、ly (isotonic control), and a clamp to lockthe column in position (isometric control). 3 EXPERIMENTS Three experiments were performed to investigate the response of the driver to steady state steering-wheel properties and to determine, firstly, the driver frame of reference, secondly； the difference
23、thresholds for the perception of force and angle, and, thirdly, the rate of growth of sensations of force and angle. The experiments were approved the Human Experimentation, Safety and Ethics Committee ofthe Institute of Sound and Vibration Research at the University of Southampton 3.1 Drivers frame
24、 of reference Frames of reference provide means for representing the locations and motions of entities in space. There are two principal classifications for reference frames in spatial perception: the allocentric (a framework external to the person), and the egocentric (a frame- work centred on the
25、person). For some tasks, the choice of reference frame may be merely a matter of convenience. In human spatial cognition and navigation the reference frame determines human perception. The haptic perception of steering-wheel position and motion is influenced by the spatial constraint imposed on the
26、wheel, which can only rotate about a column. In engineering terms, it is convenient to describe the motion of a steering wheel in a rotational frame of reference using steering-wheel torque and steering- wheel angle. However, drivers may use a different frame of reference when perceiving the feel of
27、 a steering system； they may perceive steering-wheel force rather than steering-wheel torque, and steering-wheel displacement rather than steering-wheel angle Alternatively, drivers may use neither allocentric nor egocentric frames of reference and instead may employ some intermediate reference fram
28、e as suggested by Kappers This experiment aims to test whether drivers sense steering-wheel force or torque, and whether they sense angle or displacement. The relationships between these properties are T=rF (1) x=rB (2) To investigate which variable is intuitively used by drivers, it is necessary to
29、 uncouple the relationship between rotational and translation frames of referece. This can be achieved by altering the radius of the steering wheel. It was hypothesized that, when asked to match a reference condition using isometric steering wheels (i.e. wheels chat do not rotate)with varying radii, subjects would match either the force applied by the hand or the torque applied to the steering wheel. It was similarly hypothesized that,when using isotonic steering wheels (i.e. wheels that rotate without resistance to movement) with varying radu,
