RU2009883C1 - Automatic handling manipulator control device - Google Patents

Abstract

FIELD: control systems. SUBSTANCE: device has a reversible counter, a commutator, a processing equipment transducer, two program setting units, two groups of triggers, two groups of switches, a timer, two groups of drives, two groups of position transducers, two OR gates, two groups of adders and a positioning error meter. EFFECT: improved structure. 1 dwg

Description

 The invention relates to mechanical engineering and can be used to create or upgrade supervisory control systems for transport and handling handling robots of various lifting capacities.

 A device for controlling an industrial robot is known, comprising a series-connected program setting unit, a first adder, a first amplifier and a rotation drive connected to an acceleration sensor and a first position sensor, the output of which is connected to the second input of the first adder, a differentiator, a rectifier, a waiting multivibrator connected in series, and a sampling and storage unit, as well as a second adder, a second amplifier and a radial displacement drive connected in series with the second sensor in series position, which is connected by the output to the first input of the second adder, the second input of which is connected to the second output of the program task unit, connected by the first output to the input of the differentiator, the object weight sensor and the computing unit, the output of which is connected to the third input of the first adder, the first input to the output the second position sensor, the second input with the output of the acceleration sensor, and the third input with the output of the sampling and storage unit connected by the second input to the output of the object's weight sensor.

 The disadvantage of this device when it is used in loading manipulators of high accuracy is the possibility of an uncontrolled error in the positioning of the working body of the manipulator and the cargo located on it at the object to which the cargo is being delivered.

 The prototype is a device for programmatically controlling the manipulator, containing a program task block, an element And a switch connected in series, as well as a drive associated with a position sensor for each adjustable coordinate, the output of each of which is connected to the corresponding input of the element And, a sensor of technological equipment, a reversible counter and for each adjustable coordinate, a trigger whose output is connected to the input of the drive, and the input of each of which is connected to the corresponding first output of the job block grams connected by inputs to the outputs of the reversible counter and the second output - with the input of the sensor of technological equipment, the first and second outputs of which are connected respectively to the second and third inputs of the switch, connected by the first and second inputs to the corresponding inputs of the reverse counter, the third input of which is connected to the output of the element AND.

 The prototype has the same drawback that is indicated above for the control device of an industrial robot, the possibility of uncontrolled error in the PMO. As a result, the prototype control system considered is unsuitable for use in transport and handling manipulators that require high positioning accuracy in the presence of significant elastic deformations of the links and an unstable position of the manipulator relative to the object.

 The aim of the invention is to improve the accuracy of positioning of the working body of the manipulator relative to the object on which the cargo is delivered.

 To do this, it is proposed to measure or calculate the positioning error of the manipulator's working body relative to the object to which the cargo is delivered, and then compensate for this error by correspondingly changing the coordinates of the manipulator links.

(1) где y_i1, y_i2, y_i3 - координаты точки M_i в системе координат нулевого звена;
x_i1, x_i2, x_i3 - координаты той же точки в системе координат последнего звена (рабочего органа);
А( φ₁, φ₂, . . . , φ₆) - матрица преобразования 4 х 4 из одной системы в другую, зависящая от геометрических параметров манипулятора и координат его звеньев φ₁, φ₂, . . . , φ₆.The relationship between the coordinates of the same point M _i in the coordinate system of the zero link (manipulator body, ground) and the last link (working body, cargo area) is determined by the relationship:

(1) where y _i1 , y _i2 , y _i3 are the coordinates of the point M _i in the coordinate system of the zero link;
x _i1 , x _i2 , x _i3 - coordinates of the same point in the coordinate system of the last link (working body);
A (φ ₁ , φ ₂ , ..., φ ₆ ) is a 4 x 4 transformation matrix from one system to another, depending on the geometrical parameters of the manipulator and the coordinates of its links φ ₁ , φ ₂ ,. . . , φ ₆ .

Using the dependence in the vector-matrix form, transformation (1) has the form:
Y = A χ, (2) where A, X, Y are the matrix and vectors defined above.

(3) Сокращенная запись преобразования (3) соответствует формуле (2), в сокращенной форме (2) требуется, чтобы за счет изменения координат звеньев манипулятора φ_j (j = 1, 6) было осуществлено совмещение системы реперных точек рабочего органа с их требуемыми положениями:
A( φ₁, φ₂, . . . φ₆) ˙χ^тр = А φ₁ ^тр,
φ₂ ^тр, . . . , φ₆ ^тр) ˙χ (4) где χ_тр - матрица требуемых координат реперных точек в системе координат последнего звена при условии, что звенья манипулятора имеют координаты φ₁, φ₂, . . . , φ₆;
χ - матрица координат реперных точек также в системе координат последнего звена.Formula (2) can be used to describe the coordinate transformation of not only one point, but also of a system, for example, n points. To do this, we should assume / that X and Y are matrices of n columns / in which each column is a choice of coordinates of one point:

(3) An abbreviated record of transformation (3) corresponds to formula (2), in an abbreviated form (2) it is required that, by changing the coordinates of the manipulator links φ _j (j = 1, 6), the system of reference points of the working body is combined with their required provisions:
A (φ ₁ , φ ₂ ,... Φ ₆ ) ˙χ ^tr = A φ ₁ ^tr ,
φ ₂ ^tr . . . , φ ₆ ^tr ) ˙χ (4) where χ _tr is the matrix of the required coordinates of the reference points in the coordinate system of the last link, provided that the links of the manipulator have coordinates φ ₁ , φ ₂ ,. . . , φ ₆ ;
χ is the coordinate matrix of the reference points also in the coordinate system of the last link.

The transformation matrix A (φ ₁ , φ ₂ , ..., φ ₆ ) translates the required coordinates into the coordinate system of the zero link, and the matrix A (φ ₁ ^t , φ ₂ ^t , ..., φ ₆ ^t ) coordinates of the reference points. The equality of these coordinates means the coincidence of the position of the reference points with the required.

The coordinates of the reference points χ, their required values of χ ^tr and positioning error Δχ are interconnected by the ratio:
χ ^mp = χ + Δχ. (5)
The coordinates of the reference points χ on the last link of the manipulator are its design parameters. Thus, by measuring at any position of the links of the manipulator φ ₁ , φ ₂ ,. . . , φ _{6 the} positioning error Δχ, from relation (5) we can determine the required coordinates of the reference points χ ^mp , and using relation (4) - the coordinates of the manipulator links required for precise positioning φ ₁ ^tr , φ ₂ ^tr,. . . , φ ₆ ^tr . The determination of the positioning error Δχ ² as the difference between the required and actual coordinates of the reference points, and the application of this definition to control the manipulator (formula 4 and subsequent) are original.

Relation (4) is a matrix equation for an unknown matrix A (φ ₁ ^tr , φ ₂ ^tr , ^... , φ ₆ ^tr ). In this equation, six unknowns are φ ₁ ^tr , φ ₂ ^tr,. . . , φ ₆ ^tr , and the number of scalar equations is equal to the number of elements in the first three rows of the matrices - the products A · χ ^tr and A · χ. If the matrices χ and χ _tr use one column each, then we obtain three scalar equations with six unknowns (indefinite system). For two columns in the matrix χ we obtain six equations with respect to six unknowns.

However, the system remains uncertain in physical sense, since the combination of two points means the combination of only one direct working body and one straight object, which is not enough to completely solve the positioning problem. In the general case, we have three columns in the matrices χ and χ _mp (the coordinates of three reference points) and, accordingly, a system of nine scalar equations with respect to six unknowns. However, there are only six independent equations in this system. The system is fully defined.

The system of equations (4) for three reference points determines the dependence of the required coordinates of the manipulator links φ _j ^t on the required coordinates of the reference points:
φ _j ^mp = f _j (χ ^mp ). (6)
By measuring the positioning error ΔX and applying the system of equations (4) to control the links of the manipulator, we can solve the main problem - to increase the accuracy of the positioning of the loading manipulator. However, the direct use of the result without any restrictions is difficult for two reasons. The first reason is that the proposed system is difficult to provide with sensors that measure the positioning error in the entire range of its possible values (from units of millimeters to units of meters) with high accuracy.

 The second reason is a sharp complication of the control system compared to the prototype. The prototype control device (and other manipulators of similar complexity) is a simple digital machine, and a full-fledged digital processor is required to solve a system of nonlinear algebraic equations (4). The meaning of the solution to the problem proposed below is to obtain the solution to the system of equations (4) necessary for manipulating the manipulator in a simpler way.

 The decisive moment facilitating the solution of the system of equations (4) is the fact that the transport and loading manipulator with high accuracy should ensure high positioning accuracy only with one (final) position of the working body on the object, at the point where the cargo is delivered. This circumstance can be used to simplify the problem of selecting sensors and solving the system of equations (4).

 Using software control, the working body is brought to the final position as close as possible, but with an error not less than the positioning error of the manipulator relative to the object (PMO). Further control is carried out according to the law of precise positioning (6) until the end position is reached. The approach of the working body to the final position removes both restrictions on the application of the control law (6) mentioned above. Firstly, the range of sensors that measure the positioning error is limited and, therefore, the problem of selecting sensors is simplified. Secondly, the range of values of variables for which it is necessary to solve the system of equations (4) is limited.

Δx_k, (7) где χ - матрица координат реперных точек рабочего органа при таком положении звеньев манипулятора φ₁, φ₂, . . . , φ₆, которое обеспечивает достаточную малость их расстояния до заданных координат χ^тр;
х_к - элемент матрицы х, одна из координат реперных точек;

- частные производные решений системы (4) по координатам реперных точек. Согласно (4):
f_j(X) = φ_j, тогда:

, или
φ $\genfrac{}{}{0ex}{}{\text{т}}{\text{j}}$ ^p=

Δx_k . (8)
Цель изобретения достигается тем, что в устройство для управления автоматическим транспортно-погрузочным манипулятором, содержащее коммутатор, реверсивный счетчик, первый блок задания программы, датчик технологического оборудования, триггеры первой группы, привода первой группы, датчики положения первой группы и первый элемент И, с первого по третий входы которого соединен с выходами датчиков положения первой группы, входы которой подключены к выходам приводов первой группы, с первого по третий выходы первого блока задания программы соединены с входами триггеров первой группы, а четвертый выход - с входом датчика технологического оборудования, первый и второй выходы которого подключены соответственно к первому и второму входам коммутатора, первый и второй выходы которого соединены соответственно с первым и вторым входами реверсивного счетчика, введены второй блок задания программы, таймер, второй элемент И, триггеры второй группы, переключатели первой и второй групп, приводы второй группы, датчики положения второй группы, измеритель погрешности позиционирования и сумматоры первой и второй групп, входы каждого из которых подключены к шести выходам измерителя погрешности позиционирования, выходы сумматоров первой и второй групп соединены с первыми информационными входами переключателей соответственно первой и второй групп, вторые информационные входы которых подключены к выходам соответственно триггеров первой группы и второй группы, входы которой соединены с первым и третьим выходами второго блока задания программы, четвертый выход которого подключен к входу таймера, выход которого соединен с управляющими входами переключателей первой и второй групп, а также с первым входом второго элемента И, второй вход которого подключен к выходу первого элемента И, выход - к третьим входам реверсивного счетчика и коммутатора, а третий, четвертый и пятый входы - к выходам датчиков положения второй группы, входы которой соединены с выходами приводов второй группы, входы которой подключены к выходам переключателей второй группы, а выходы переключателей первой группы соединены с входами приводов первой группы.At a small distance from the final position of the working body, the solution (6) of the system of equations (4) allows linearization in its arguments:
φ $\genfrac{}{}{0ex}{}{\text{t}}{\text{j}}$ = f _j (χ) +

Δx _k , (7) where χ is the coordinate matrix of the reference points of the working body at this position of the manipulator links φ ₁ , φ ₂ ,. . . , φ ₆ , which provides a sufficient smallness of their distance to the given coordinates χ ^tr ;
x _to - an element of the matrix x, one of the coordinates of the reference points;

- partial derivatives of the solutions of system (4) with respect to the coordinates of the reference points. According to (4):
f _j (X) = φ _j , then:

, or
φ $\genfrac{}{}{0ex}{}{\text{t}}{\text{j}}$ ^p =

Δx _k . (8)
The purpose of the invention is achieved in that in a device for controlling an automatic transport and handling manipulator, comprising a switch, a reversing counter, a first program setting unit, a process equipment sensor, triggers of the first group, a drive of the first group, position sensors of the first group and the first element And, from the first the third inputs of which are connected to the outputs of the position sensors of the first group, the inputs of which are connected to the outputs of the drives of the first group, from the first to third outputs of the first block of the program task connected to the inputs of the triggers of the first group, and the fourth output - with the input of the sensor of technological equipment, the first and second outputs of which are connected respectively to the first and second inputs of the switch, the first and second outputs of which are connected respectively to the first and second inputs of the reversible counter, the second task unit is introduced programs, timer, second element AND, triggers of the second group, switches of the first and second groups, drives of the second group, position sensors of the second group, positioning error meter and totalizers of the first and second groups, the inputs of each of which are connected to six outputs of the positioning error meter, the outputs of the adders of the first and second groups are connected to the first information inputs of the switches of the first and second groups, the second information inputs of which are connected to the outputs of the triggers of the first group and second group, respectively , the inputs of which are connected to the first and third outputs of the second block of the program task, the fourth output of which is connected to the timer input, the output of which is connected to the control inputs of the switches of the first and second groups, as well as with the first input of the second element And, the second input of which is connected to the output of the first element And, the output - to the third inputs of the reversible counter and switch, and the third, fourth and fifth inputs - to the outputs of the second position sensors group, the inputs of which are connected to the outputs of the drives of the second group, the inputs of which are connected to the outputs of the switches of the second group, and the outputs of the switches of the first group are connected to the inputs of the drives of the first group.

 The drawing shows a functional diagram of a device for controlling an automatic transport and handling manipulator. It contains a reversible counter 1, a switch 2, a sensor 3 of technological equipment, the first 4 and second 5 blocks of the job program, the first 6 and second 7 groups of triggers, the first 8 and second 9 groups of switches, timer 10, first 11 and second 12 groups of drives, the first 13 and second 14 groups of position sensors, the first 15 and second 16 elements And, the first 17 and second 18 groups of adders and the meter 19 positioning error.

The device for controlling the automatic transport and handling manipulator operates in two modes:
mode I software positioning corresponding to the operation of the prototype;
mode II, proposed for solving the problem of precise positioning.

 Switching from mode I to mode II is performed by the signal of the timer 10, which is turned on by the signal of the second block 5 of the program job for the time necessary to perform accurate positioning and the necessary technological operations in this mode.

 In mode I, the switches of the first 8 and second 9 groups pass control signals from the triggers of the first 6 and second 7 groups to the drives of the first 11 and second 12 groups, and timer 10 generates a logical unit signal to the second element And 16. In mode II, the signal of the timer 10 switches the drives of the first 11 and second 12 groups from the first 6 and second 7 groups of triggers to the first 17 and second 18 groups of adders and blocks the operation of the second element And 16 with a logic zero signal.

 In mode I, the manipulator works out the program that is assigned to it by the first 4 and second 5 blocks of the program task (in the proposed control device, the number of drives is increased in comparison with the prototype from 3 to 6 to provide control of the working body orientation). This program is a series of fixed sets of coordinates of manipulator links.

 The development of these fixed sets is as follows. All sets of fixed coordinates are numbered: 0, 1, 2,. . . The first 4 and second 5 blocks of the program assignment give out to the drives of the first 13 and second 14 groups that set of coordinates, the number of which indicates the reversible counter 1. Depending on the state of the sensor 3 of the technological equipment and switch 2, two operating modes are possible: summing and subtracting . Groups 6, 7, 13 and 14 and elements 15 and 16 limit the speed of the program so that each set of fixed coordinates has time to work out with the necessary accuracy.

 To carry out such control, when issuing each next set of coordinates, the triggers of the first 6 and second 7 groups are set to the single state of those drives whose coordinates are changed. The drives work out new coordinates until the position sensors of the first 13 and second 14 groups record that all the drives have arrived at the given coordinates. The signals from groups 13 and 14 of the position sensors set the triggers of the first 6 and second 7 groups to zero and are transmitted to the first 15 and second 16 elements I. Elements I 15 and 16 after the completion of working out all the given coordinates allows the switch 2 to change the state of the reverse counter 1 (+1 or -1) and go to work out the next set of coordinates.

 The manipulator operation mode I is unacceptable for some applications due to the presence of an error in the positioning of the manipulator relative to the object. This disadvantage is eliminated when operating in mode II as follows. At points of the program where it is necessary to provide more accurate positioning, the second block 5 of the program task starts the timer 10, which switches with the logical "0" using the switches of the first 8 and second 9 groups all the drives of the first 11 and second 12 groups from the rough positioning system to an accurate positioning system, that is, it connects to the outputs of the switches of the first 17 and second 18 groups. This allows you to implement formula (8) for calculating the errors of the coordinates of the links.

> ε_j (ε - зона нечувствительности привода), отрабатывает ошибку положения соответствующего звена. В результате все соответствующие ошибки позиционирования Δ х_к стремятся к нулю, а при условии:

< ε_j, j =

все составляющие ошибки позиционирования оказываются достаточно малыми. Их отработка прекращается по сигналу таймера 10, который сигналом логической "1" вновь возвращает устройство в режим программного управления (режим I).Each of the adders calculates the coordinate correction Δφ _j ^tr for the corresponding link of the manipulator in accordance with the dependence (8). Each of the drives that receives the signal

> ε _j (ε is the drive deadband), fulfills the position error of the corresponding link. As a result, all relevant positioning errors Δ x _k tend to zero, and provided:

<ε _j , j =

all components of positioning errors turn out to be quite small. Their development is terminated by the signal of timer 10, which, with a logical "1" signal, returns the device to program control mode (mode I).

 The invention improves the accuracy of positioning of the working body of the manipulator relative to the object on which the cargo is delivered. Simulation on a digital computer shows that the positioning error of an automatic transport and handling manipulator for some applications can be reduced by 5. . . 10 times (from 50 to 5 mm). This, in turn, leads to increased productivity, reliability and safety of the manipulator. (56) Copyright certificate of the USSR N 1442392, cl. B 25 J 9/00, 1987.

Claims (1)

 DEVICE FOR CONTROLLING AUTOMATIC TRANSPORT AND LOADING MANIPULATOR, containing a switch, a reversible counter, the first block of the program setting, a process equipment sensor, a relay, first group position sensors, the inputs of which are connected to the outputs of the first group outputs, from the first to third outputs of the first program unit are connected to the inputs of the first group of triggers, and the fourth move - with the input of the technological equipment sensor, the first and second outputs of which are connected respectively to the first and second inputs of the switch, the first and second outputs of which are connected respectively with the first and second inputs of the reversible counter, which is used to increase the accuracy , it includes the second program unit, timer, second AND element, second group triggers, first and second group switches, drives, positioning error meter, and first and second totals the first group, the inputs of each of which are connected to the six outputs of the positioning error meter, the outputs of the first and second group adders are connected to the first information inputs of the switches, respectively, the first and second inputs, and the second information outputs connected to the first, second and third outputs of the second block of the program definition, the fourth output of which is switched to the input of the timer, the output of which is connected to the control inputs of the switch the first and second groups, as well as with the first input of the second AND element, the second input of which is connected to the output of the first AND element, the output to the third inputs of the reversible counter and switch, and the third, fourth and fifth inputs to the outputs of the second position sensor the inputs of which are connected to the outputs of the drives of the second group, the inputs of which are connected to the outputs of the switches of the second group, and the outputs of the switches of the first group are connected to the inputs of the drives of the first group.

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