Szybkobieżne Pojazdy Gąsienicowe (35) nr 2, 2014

Prof. Gabriel KOST, Dr. Andrzej DYMAREK, Dr. Tomasz DZITKOWSKI – Silesian University of Technology, Gliwice

Gabriel KOST Andrzej DYMAREK Tomasz DZITKOWSKI

EXPERIMENTAL DETERMINATION OF PERCEPTIBLE ACCELERATION OF A DRIVING SIMULATOR FOR PEOPLE WITH

DISABILITIES

Abstract. This paper presents the results of experimental determination of actual accelerations in a car simulator in typical traffic situations. Key physical quantities were measured in characteristic points of the simulator during acceleration, braking, turning, changing lanes, etc.

Keywords: simulator, Stewart platform, parallel robot.

1. INTRODUCTION

Work on the design of a mechatronic integrator of control procedures of a vehicle simulator for disabled people commenced with a general plan of design activities. For this purpose an outline of the functional structure was prepared including all necessary subsystems [1 - 9]. The final developed and implemented simulator structure is shown in Fig. 1.

1

2

3

4

6

5

7 Fig. 1. Model of the selected concept of simulator stand

Simulator subsystems: 1 - Stewart platform with a Fiat Panda car body mounted onto it, 2 - system of three rigid screens and projectors mounted on support frame, 3 - rigid rear screen, 4 - lift for facilitating getting into the car, 5 - instructor's stand,

6 - protecting fence around simulator stand, 7 - simulator room.

Gabriel KOST, Andrzej DYMAREK, Tomasz DZITKOWSKI

All interactions between the selected components converge in the central part, the master control computer, which enables operating in real time.

The purpose of the simulator analysed here is to enable people with disabilities to virtually drive a vehicle adapted to their dysfunction under conditions that are stress-free and safe for them and for the surroundings. Observation and analysis of trainee behaviour when driving the simulator will initially verify his or her skills and capabilities of driving a car. This is to be provided by training conditions as similar as possible to real traffic conditions, including the perception of load occurring while driving. In this paper we compare the measurement results of kinematic quantities recorded when driving a car on a road [2, 6] with the results of experiments with a mechatronic integrator that simulates car driving.

2. SUBJECT OF THE STUDY

The subject of the study is a driving training simulator for people with disabilities shown in Fig. 1. The experimental stand comprises the following measuring instruments:

� system of sensors for recording such kinematic quantities as rotation around the three coordinate axes, acceleration along the three principal axes. The advantage of the proposed system of sensors is synchronised operation and the capability to measure as many as 6 kinematic quantities by each of the sensors individually. The measuring system of the sensors can be connected to a portable data logging and processing device (Fig. 2B),

� a high-speed camera system for recording motion at a frequency of 1000 Hz with a portable computer for registering data in the form of images and processing them into data required for analysing the motion of the platform and behaviour of the vehicle driver (Fig. 2A).

The aim of the conducted kinematic analysis is the recording of the motion of characteristic points of the simulator. The recorded actual values of kinematic quantities help determine simulator behaviour, tune the drives to selected simulations of the platform of the driving simulator for people with disabilities. The test stand will also provide information on loads acting on the car body and on the vehicle driver. Such information will be an important input into the analysis of undesired interactions registered during selected simulations.

Kinematic analysis of a driving simulator for disabled people

Fig. 2. Structure of the test stand for analysing motion of a driving simulator for people

with disabilities

Sensors for measurements were attached to the tested object in three characteristic points: on the Stewart platform – sensor 1, on headrest of the driver's seat – sensor 2, and on front bumper of simulator body – sensor 3 (Fig. 3).

A B

Gabriel KOST, Andrzej DYMAREK, Tomasz DZITKOWSKI

Fig. 3. Tested object and points of attaching sensors

Tests were conducted for the following events in simulator operation:

� acceleration to 60 km/h, concluded with braking to stop,

� acceleration to 90 km/h, concluded with braking to stop,

� acceleration to 130 km/h and braking to 100 km/h,

� driving along an arc at 50 km/h.

3. COMPARATIVE STUDIES

In order to compare the results of tests carried out on the real object and on the simulator, four events of operation of each of the systems were selected, these events having identical acceleration characteristics:

� linear acceleration during driving simulation at up to 60 km/h concluded with braking to stop, depicted in Figs. 4 and 5 (event 1),

Kinematic analysis of a driving simulator for disabled people

Fig. 4. Acceleration of the real system

Fig. 5. Acceleration of the simulator system a) sensor 1 b) sensor 2 c) sensor 3

a) b)

c)

Gabriel KOST, Andrzej DYMAREK, Tomasz DZITKOWSKI

� linear acceleration during driving simulation at up to 130 km/h and braking from maximum speed down to 100 km/h, depicted in Figs. 6 and 7 (event 2),

Fig. 6. Acceleration characteristics in the real system

Fig. 7. Acceleration of the simulator system a) sensor 1 b) sensor 2 c) sensor 3

a) b)

c)

a) b)

c)

Kinematic analysis of a driving simulator for disabled people

� linear acceleration during driving simulation along an arc at 50 km/h, depicted in Figs. 8 and 9 (event 3),

Fig. 8. Acceleration characteristics in the real system

Fig. 9. Acceleration of the simulator system a) sensor 1 b) sensor 2 c) sensor 3

a) b)

c)

Gabriel KOST, Andrzej DYMAREK, Tomasz DZITKOWSKI

� linear acceleration during driving simulation at 90 km/h, depicted in Figs. 10 and 11 (event 4).

Fig. 10. Acceleration characteristics in the real system

Fig. 11. Acceleration of the simulator system a) sensor 1 b) sensor 2 c) sensor 3

a) b)

c)

Kinematic analysis of a driving simulator for disabled people

Based on the results recorded during the experiment, it was found that the load directions occurring during the simulation are consistent with those expected - observation and analysis of the obtained acceleration characteristics showed high similarity of the shape of the acceleration components with the characteristics obtained during tests on the real object. The tuning of the simulator should be effected through the amplification of acceleration signal acting upon it in order to create sensible loads as close to the real ones as possible. Table 1 lists the maximum and minimum values of acceleration read from graphs in Figs. 4 - 11.

Table 1. Extreme values of acceleration Event Real system Simulator

Max. (m/s2) Min. (m/s2) Max. (m/s2) Min. (m/s2)

1 2.2 -6 0.8 -1.4

2 2.5 -3 0.6 -1.2

3 0.4 -6 0.2 -0.4

4 6.4 -4 0.4 -0.7

Finally, it is concluded that the simulator drives meet the set requirements of reproducing motion of a real system in the simulator motion. The sensations of the simulator user, however, are much milder than in a real system. The conducted tests confirmed the correctness of the structure and its control, and the only quantity that enhanced sensations when using the simulator was its acceleration.

4. CONCLUSIONS

The goal of the conducted tests was to gather information on the behaviour of a moving simulator. The simulator was tested under various operating conditions: acceleration to 60 km/h, concluded with braking to stop; acceleration to 90 km/h, concluded with braking to stop; acceleration to 130 km/h and braking to 100 km/h; driving along an arc at 50 km/h.

As the result of measurements made during the experiment it was found that:

� the load directions occurring during the simulation are consistent with those expected - observation and analysis of the obtained acceleration characteristics showed high similarity of the shape of the acceleration components with the characteristics obtained during tests on the real object,

� the tuning of the simulator should be effected through the amplification of acceleration signal acting upon it in order to create sensible loads as close to the real ones as possible.

The obtained results of behaviour study of characteristic components of the simulator form a data set to be used at the stage of testing, adjusting and tuning of subsystems of a mechatronic integrator of control procedures for a vehicle simulator for people with disabilities.

Gabriel KOST, Andrzej DYMAREK, Tomasz DZITKOWSKI

6. REFERENCES

[1] Banaś W., Dymarek A., Dzitkowski T., Gołda G., Herbuś K., Kost G., Ociepka P.: Simulator for teaching how to drive a car for people with disabilities. International Scientific and Engineering Conference – Automation Problems Ideas Solutions. Sevastopol 2011, pp. 91-92.

[2] Banaś W., Dymarek A., Dzitkowski T., Herbuś K., Kost G., Ociepka P., Reclik D.: Experimental determination of perceptible acceleration exerted on the driver of a passenger car. 18th International Scientific and Engineering Conference - Machine-Building and Technosphere on the Border of the XXI Century, Donetsk – Sevastopol 2011, Vol. 4, pp. 14-17.

[3] Banaś W., Dymarek A., Dzitkowski T., Gołda G., Herbuś K., Kost G., Ociepka P.: Concept of a simulator for teaching how to drive a car for people with disabilities. 18th International Scientific and Engineering Conference - Machine-Building and Technosphere on the Border of the XXI Century, Donetsk – Sevastopol 2011, Vol. 4, pp. 10-14.

[4] Ociepka P., Herbuś K., Dymarek A., Dzitkowski T.: Koncepcja symulatora do nauki jazdy samochodem dla osób niepełnosprawnych. Wybrane Problemy Inżynierskie. 2011, pp. 293-298.

[5] Kost G., Reclik D., Banaś W., Dzitkowski T., Dymarek A., Ociepka P., Herbuś K., Gołda G.: Koncepcja symulatora do nauki jazdy samochodem dla osób niepełnosprawnych: założenia systemu, określenie wymaganych przyspieszeń metodami eksperymentalnymi w ruchu ulicznym. Pomiary Automatyka Robotyka. 2/2012, p. 89.

[6] Dymarek A., Dzitkowski T., Herbuś K., Kost G., Ociepka P.: Determination of Acceleration of a Car’s Passenger as the Base for Designing of a Simulator for how to Drive a Car for Disabled People. Lecture Notes in Information Technology, Vol. 15, 2012, pp. 439-442.

[7] Dymarek A., Dzitkowski T., Herbuś K., Kost G., Ociepka P.: Geometric analysis of motions exercised by the Stewart platform. Advanced Materials Research. Vol. 837, 2014, pp. 351-356.

[8] Dymarek A., Dzitkowski T., Herbuś K., Kost G., Ociepka P.: The Simulator for Teaching How to Drive a Car for People with Disabilities. Solid State Phenomena, Vol. 198, 2013, pp. 427-432.

[9] Dymarek A., Dzitkowski T.: The Inverse Problem of Kinematics as the Tool for Determination of Motion Trajectories Exercised by Worm Drives of a Stewart Platform. Advanced Materials Research. Vol. 837, 2014, pp. 357-362.

EXPERIMENTAL DETERMINATION OF PERCEPTIBLE ACCELERAT ION OF A CAR SIMULATOR FOR PEOPLE WITH DISABILITIES

Abstract: This paper presents the results of experimental determination of actual accelerations in a car

simulator in typical traffic situations. Key physical quantities were measured in characteristic points of the simulator during acceleration, braking, turning, changing lanes, etc.

Keywords: simulator, Stewart platform, parallel robot.