SK500612017A3 - Controlled actuator with pneumatic artificial muscles - Google Patents

Abstract

The controlled pneumatic artificial muscle antagonist actuator is formed by a base plate (1) with fixedly connected two columns (2) to which bearing bushes (3) are fixed, through which the pushed shaft (4) is fixedly connected to the pulley (5). On the end of the shaft (4), the hub of the arm (6) is fixedly fixed, which is firmly connected to the arm (7), at the end of which the load (8) is fixed. At the same time, a flexible strip (9), which connects the ends of both pneumatic artificial muscles (10) and (11), whose opposite ends are attached to the rear brackets (12) and which are rigidly attached to the base plate (1), is threaded over the pulley (5). ). Pneumatic artificial muscles (10) and (11) are connected to tubes (13) and (14) to manifolds (15) and (16) which are tubes (17) and (18) connected to discharge electropneumatic valves (19) and (20). These are tubes (21) and (22) connected to the pneumatic throttle valves (23) and (24). Tubes (25) and (26) are connected to the distribution members (15) and (16) and are connected to the electropneumatic inlet valves (27) and (28). Tubes (29) and (30) are connected thereto and are then connected to a manifold (31), which is a tube (32) connected to a source of compressed air (33). From the electropneumatic valves (19), (20) and (27), (28), the control connections (34), (35) and (36), (37) are provided.

Description

Technical field

The invention relates to the control of an antagonist actuator with pneumatic artificial muscles in the field of automation, robotics and mechatronics, where light, powerful, movable and steerable drives are usually used.

BACKGROUND OF THE INVENTION

Current rotary motion generating devices by means of pneumatic artificial muscles (hereinafter referred to as artificial muscles) are designed as mechanical systems with two fixed anchored artificial muscles, which are connected by their ends by a flexible bending band. This belt is threaded onto the circumference of the rotating roller which is slid onto the actuator shaft and is mounted in bearings. These are located at the ends of the support pillars of the actuator. The actuator thus constitutes an assembly where the columns are mounted on the support plate and at their ends there are bearings, a shaft and a load arm, with the artificial muscles positioned along the columns. Artificial muscles are attached with opposite ends by a holder connected to the posts. Such an artificial muscle actuator in antagonist engagement forms a relatively long and slender whole with satisfactory weight and size characteristics. Each artificial muscle of the actuator has a certain tensile force, and it is transmitted via a pulley to a muscle which acts by its tensile force against the tensile force of the first artificial muscle. At the same filling pressures in both muscles, the tensile forces are equal at the same values of their contractions and the actuator arm stabilizes at a position which is considered the initial condition of the actuator. In this initial position (at a certain air pressure in artificial muscles), the actuator has a certain stiffness, the highest stiffness at the maximum air pressure in both artificial muscles. In case of unequal filling pressures in the artificial muscles, the arm of the actuator stabilizes in a position corresponding to the equal tensile forces of the two muscles. The angular deflection of the actuator arm, which is subjected to an external load with a certain weight, depends on the radius of the pulley and the magnitude of changes in artificial muscle lengths (dilatation, contraction), when pressure (air volumes) changes in individual artificial muscles. For a certain shoulder rotation, the length of each muscle changes by the same amount, while the contraction of one muscle increases and the other decreases. The stiffness of such a mechanism can be varied according to the stated requirement since the position of the arm is proportional to the difference in muscle pressure, while the stiffness is proportional to the sum of the muscle pressure. The same pressure difference can be achieved at different sum values, which means that the same arm deflection can be achieved at different stiffnesses. The function of current artificial muscle antagonist actuators is provided by increasing the pressure (volume) of air in one muscle and simultaneously reducing the pressure (volume) in the other (antagonist) muscle. In this case, both artificial muscles are active and require simultaneous control of the amount of air pressure to the individual muscles. It is difficult to control, since at any point in time it is necessary to maintain the condition of equality between the pressure increase (air volume) in one artificial muscle and the pressure loss (air volume) in the other artificial muscle. This requires the need to simultaneously control four electropneumatic valves to control two artificial muscles. Otherwise, the actuator arm movement is uneven (tearing) and the actuator stiffness value fluctuates. Such requirements for driving an artificial muscle actuator are very demanding and complicate the solution to this problem. This issue of pneumatic artificial muscle control is presented in many sources, such as:

VanHam, R., Daerden, F., Verrelst, B., Lefeber, D .: Control of aJoint Actuated by Two Pneumatic Artificial Muscles with Fast Switching ON-OFF Valves. Proceedings of the 6th National Congress on Theoretical and Applied Mechanics, Ghent, 2003, 8 p.

Jien, S., Hirai, S., Ogawa, Y., Ito, M., Honda, K .: Pressure Control Valve for Mckibben Artificial Muscle Actuators with Miniaturized Unconstrained Pneumatic ON / OFF Valves. IEEE / ASME International Conference on Advanced Intelligent Mechatronics (AIM 2009), Singapore, 2009 1383-1388.

Jouppila, V.T., Gadsden, S.A, Bone, G.M., Ellman, A.U., Habibi, S.R .: Sliding Mode Control of a Pneumatic Muscle Actuator System with a PWM strategy. International Journal of Fluid Power, Vol. 15, Issue 1,2014, s. 19-31.

More, M., Líška, O .: Comparison of Different Methods for Pneumatic Artificial Muscle Control. llth IEEE International Symposium on Applied Intelligence and Informatics (SAMI 20I3), Herľany, 2013, pp. 117-120.

Fluidic Artificial Muscle Actuation System for Trailing-Edge Flap, US 20110266391 A1.

Fluid-Driven Artificial Muscles as Mechanisms for Controlled Actuation, US 7837144 B2.

SUMMARY OF THE INVENTION

These drawbacks are overcome by the present invention, which is based on the application of the actuator control concept with different pneumatic artificial muscles. One of the pneumatic artificial muscles (passive) in the respective half of the actuator arm path acts as a passive non-linear pneumatic spring and does not need any steering intervention. It is directed only to the antagonistic complement (active) artificial muscle, the movement of which is controlled and the position adjusted by regulation of the air pressure in the muscle. In the second half of the arm path, the actuator function is the same, there is confusion between the functions of the pneumatic artificial muscles. Such simplified control of the antagonist actuator with pneumatic artificial muscles is made possible by the appropriate design of the actuator. The controlled actuator consists of a base plate with fixedly connected two columns to which are fixedly connected the bearing bushes, through which the shaft is slid, fixedly connected to the pulley. At the end of the shaft there is a fixed slide of the arm hub, which is fixedly connected to the arm, at the end of which the load of the actuator is fixed. At the same time, a flexible belt is passed through the pulley, which connects the ends of both pneumatic artificial muscles. Their opposite ends are connected to the rear brackets and these are attached to the base plate. Such an actuator has pneumatic artificial muscles via inlet tubes connected to manifolds which are connected to the discharge electropneumatic valves by additional tubes. These are connected by pipes to pneumatic throttles. Tubes are also connected to the manifolds and connected to the electropneumatic inlet valves by opposite ends. Connected to them are tubes, which are subsequently connected to a manifold which is connected by a tube to a source of compressed air. All electropneumatic valves are connected to the control connections to activate the valve.

The advantage of the proposed actuator control solution is that it requires only one electro-pneumatic valve to be controlled at a time. Changing the direction of movement of the arm changes the control electro-pneumatic valve, but never controls more than one electro-pneumatic valve at the same time. Such (single parameter) control of an antagonist actuator with pneumatic artificial muscles is substantially simpler than the original (multi-parameter) control and also allows the actuator to operate in the full range of compressed air pressure. This is manifested in the form of higher stiffness of the actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution is explained in more detail by means of the drawing, where FIG. 1 shows the overall arrangement of the functional parts of the device.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 shows an exemplary embodiment of the invention for realizing the proposed control of an antagonist actuator with pneumatic artificial muscles. It shows the overall arrangement of the functional parts of the device, the control being made possible by a suitable design of the actuator. The guided antagonist actuator with pneumatic artificial muscles consists of a base plate 1 with two columns 2 fixedly connected to which bearing bushes are fixedly connected

3, through which the shaft 4 is fixed, connected to the pulley 5. At the end of the shaft 4, the hub of the arm 6 is fixed, connected to the arm 7, at the end of which the load 8 is attached. 9, which connects the ends of the two pneumatic artificial muscles 10 and 11, the opposite ends of which are connected to the rear holders 12 and which are fixedly connected to the base plate 1. Said actuated actuator has pneumatic artificial muscles 10 and 11 by tubes 13 and 14 connected to the splitting members. 15 and 16, which are connected by tubes 17 and 18 to the discharge electropneumatic valves 19 and 20. These are connected by tubes 21 and 22 to the pneumatic throttle valves 23 and 24. To the manifold members 15 and 16 are connected tubes 25 and 26 which are connected The electro-pneumatic valve 27 and 28 are connected thereto. Tubes 29 and 30 are connected thereto and these are then connected to the manifold 31 which is A control 32 is connected to the compressed air source 33 from the electro-pneumatic valves 19. 20 and 27.28.

Industrial usability

A controlled antagonist actuator with pneumatic artificial muscles can be used in both short and long term applications of functional units in which pneumatic muscles are used in antagonistic or other engagement. The proposed method of control can be used in the field of automation, robotics and mechatronics, where light, powerful, movable and controllable drives are usually used.

Claims (1)

PATENT CLAIMS Controlled pneumatic muscle antagonist actuator, characterized in that it consists of an actuator consisting of a base plate (1) with fixedly attached two columns (2), to which bearing bushes (3) are fixedly connected, through which the shaft (4) is slid. fixedly connected to the pulley (5), wherein at the end of the shaft (4) there is a fixed slide of the arm (6) which is fixedly connected to the arm (7) at the end of which the load (8) is fixed a flexible band (9) for connecting the ends of the pneumatic artificial muscles (10) and (11), the opposite ends of which are connected to the rear supports (12) and which are connected to the base plate (1), said actuator having pneumatic artificial muscles (10) and (11) pipes (13) and (14) connected to manifolds (15) and (16) which are pipes (17) and (18) connected to discharge electropneumatic valves (19) and (20), which are connected by tubes (21) and (22) to the tires (23) and (24), the manifolds (15) and (16) being connected to tubes (25) and (26), which are connected to the inlet electropneumatic valves (27) and (28), to which the tubes (29) and (30) are connected, and these are subsequently connected to a manifold (31) which is connected by a tube (32) to a source of compressed air (33), from electro-pneumatic valves (19), (20) and ( 27), (28) the control connections (34), (35) and (36), (37) are provided.