SK288197B6 - Actuator with artificial muscles - III. - Google Patents

Abstract

Actuator with artificial muscles III. is formed by a base plate (1) firmly attached to the two uprights (2), to which are firmly attached to the bearing housings (11). Is not inserted through the shaft (3) rigidly fixed to the cam (4), after which the flexible strip passing through (5), whose ends are connected to the artificial muscle (6), and these muscles are attached to opposite ends of the rear support (7) . At the same time the shaft (3) securely engaged with the hub arms (12), which is connected with the arm (8), and it is connected to a load (9).

Description

The technical solution relates to an actuator with artificial muscles III. Artificial muscle actuator is an automation and robotics device where light, powerful and movable drives are common.

BACKGROUND OF THE INVENTION

Current rotary motion generating devices using artificial muscles are designed as mechanical systems with two rigidly anchored artificial muscles that are connected by opposite ends with a flexible bending band. This belt is threaded onto the circumference of the rotary 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. Such an actuator forms a relatively long and slender unit with satisfactory weight and size characteristics. In the case of the application of pneumatic artificial muscles, this device significantly exhibits a non-linear relationship between the varying air pressure entering the artificial muscles and the angle of rotation of the arm mounted on the actuator output shaft. This characteristic has a shape similar to a logarithmic curve, the nature of such a non-linearity (type of saturation) causes a decrease in the actuator torque at larger position values (rotation). This phenomenon is caused by the properties of the artificial muscles used, mainly because the constructors of the actuators are trying to utilize the extent of contraction (contraction) of the artificial muscles to the full. This also fully manifests the non-linear properties of artificial muscles, which are very pronounced in these circumstances. The drive with such an actuator has insufficient and asymmetric stiffness at larger turns. Accurate position control of such a system is complicated and its capabilities are limited.

SUMMARY OF THE INVENTION

These drawbacks are overcome by the proposed technical solution, which is based on the concept of generating a constant (or varying to a small extent) torque on the actuator shaft by applying an axially symmetrical cam instead of a circular roller. The actuator operates in such a way that the initial position of the arm is adjusted by filling both artificial muscles to a certain (maximum) pressure of the gaseous medium (air). Muscles, due to the same contraction, define the position of the actuator arm to the reference (initial) position (parallel to the longitudinal axis of the actuator). By discharging the gas from one artificial muscle, it is prolonged and at the same time the other artificial muscle contractions, which is still under initial pressure. This action causes the bending of the flexible belt and, at the same time, the decoupling of the pulley accompanied by the rotation of the shaft. Each rotation of the shaft (caused by the loss of a certain volume of air from the respective artificial muscle) is determined by the torque equality between the artificial muscles. As the torque from both artificial muscles decreases with increasing rotation, the stiffness of the actuator in both directions decreases as well. This is a consequence of a non-linear decrease in the strength of artificial muscles depending on their contraction. Due to the constant radius of the pulley, the torque characteristic of the actuator is also non-linear. Remove, respectively. suppression of this phenomenon is possible when, instead of a constant-radius pulley, we apply a pulley with a radius increasing depending on the rotation of the shaft, i. j. axially symmetrical cam rollers. If it is suitably shaped, it is possible to achieve a small (or zero) drop in the torque on the actuator shaft in comparison with the initial and thus a proper and symmetrical stiffness of the actuator. The proposed technical solution envisages the use of a cam with any surface, i.e. j. toothed for chain or toothed belt drives, possibly with a smooth surface for flat, V-belts, for cable ducts and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution is explained in more detail by means of the drawings. 1 shows the overall arrangement of the functional parts of the device in front view, and FIG. 2 shows the overall arrangement of the functional parts of the device in a side view.

SK 288197 Β6

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 and FIG. 2 shows an embodiment of the invention. It shows the overall arrangement of the functional parts of the device. Artificial muscle actuator III. It consists of a base plate I with two columns 2 fixedly connected to which the bearing bushes LL are fixedly connected. A shaft 3 fixedly connected to the cam 4 is inserted through the shaft 4, after which a flexible strip 5 is connected. At the same time, the hub 12 of the arm 12, which is connected to the arm 8, is fixedly attached to the shaft 3, and this is connected to the load 9.

Industrial usability

The device according to the proposed solution can be used in short and long term application of functional units in which pneumatic or other artificial muscles are used in individual, antagonistic or other connection. The system of the device can also be used on other actuators (electric, hydraulic), their dimensions and performance depend on the size of the equipment used. The device can be used individually, but they can be mechanically interconnected into more complex units (eg in robotics).

Claims (1)

Artificial muscle actuator, characterized in that it consists of a base plate (1) with two columns (2) fixedly connected to which the bearing bushes (11) are fixedly connected, through which the inserted shaft (3) is fixedly connected to the cam ( 4), after which the flexible strip (5), whose ends are 25 are connected to the artificial muscles (6), and these are attached to the rear brackets (7) with opposite ends, and at the same time the hub (3) of the arm (12), which is connected to the arm (8), is fixed with load (9).