Control system and method for controlling the movement of an aerial apparatus

Abstract

The present invention is related to a control system for controlling the movement of an aerial apparatus, in particular for controlling a turnable ladder of a firefighting vehicle, comprising a manually operable input device that is deflectable in at least one spatial direction by a deflecting force, an processing unit for converting the amount of deflection of the input device into a corresponding speed signal and an actuating unit for moving the aerial apparatus with a speed corresponding to the speed signal. The invention is characterized by determining means for determining a possible maximum speed and restricting means for counteracting or limiting the deflection of the input device according to the determined possible maximum speed.

Claims

1. A control system for controlling the movement of an aerial apparatus, in particular for controlling a turnable ladder of a firefighting vehicle, the control system comprising: a manually operable input device that is deflectable in at least one spatial direction by a deflecting force, a processing unit for converting the amount of deflection of the input device into a corresponding speed signal and an actuating unit for moving the aerial apparatus with a speed corresponding to the speed signal, determining means for determining a maximum speed for moving the aerial apparatus, and restricting means for counteracting or limiting the deflection of the input device according to the determined maximum speed.

2. The control system according to claim 1, wherein the restricting means is provided to apply a restoring force according to the determined maximum speed to the input device acting to restore the input device against the deflecting force.

3. The control system according to claim 1, wherein the input device is a joystick.

4. The control system according to claim 1, wherein the determining means comprise at least one of the following: speed sensors, acceleration sensors, load sensors, deflection sensors, and distance sensors for determining a distance to an object.

5. The control system according to claim 4, wherein the determining means is provided for determining a maximum speed on the basis of measured sensor data and predetermined data related to construction parameters of the aerial apparatus to be controlled.

6. A method for controlling the movement of an aerial apparatus, in particular for controlling a turnable ladder of a firefighting vehicle, the method comprising the steps of: deflecting a manually operable input device associated with the aerial apparatus in at least one spatial direction by a deflecting force; converting the amount of deflection of the input device into a corresponding speed signal; and moving, with an actuating unit, the aerial apparatus with a speed corresponding to the speed signal, wherein a maximum speed for moving the aerial apparatus is determined, and the deflection of the input device is counteracted or limited according to the determined maximum speed.

7. The method according to claim 6, wherein a restoring force according to the determined maximum speed is applied to the input device acting to restore the input device against the deflecting force.

8. The method according to claim 7, wherein a maximum speed is determined on the basis of measured sensor data and predetermined data related to construction parameters of the aerial apparatus to be controlled.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The only FIG. 1 is a schematic view of the layout of an embodiment of a control system for controlling the movement of an aerial apparatus according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) The control system 10 shown in the FIGURE is provided for controlling a turnable ladder of a firefighting vehicle as one example of an aerial apparatus. It is noted that the control system according to the present invention is not restricted to the control of such turnable ladders but is applicable also to other kinds of aerial apparatuses. The control system 10 comprises a joystick 12 as one embodiment of an input device which is manually operable. As commonly known, the joystick 12 is deflectable in different spatial directions (e.g., up, down, left and right) by a deflection force that can be applied manually by an operator (not shown). Thus, the joystick, which is shown in a neutral central position can be deflected by tilting it sidewards. This tilting movement comprises a direction component, defined by the direction into which the joystick 12 is deflected, and an absolute value corresponding to the amount of deflection, corresponding to an intended speed of movement into the given direction. The amount of deflection of the joystick 12 is converted into a corresponding speed signal by means of processing unit 14, which senses the direction of deflection of the joystick 12 as well as the amount of its deflection and converts it into a corresponding electric speed signal, which is output by the processing unit 14 and input into an actuating unit for moving the turnable ladder with a speed corresponding to the present speed signal. For example, the actuating unit 16 is a hydraulic unit that outputs a hydraulic pressure for moving the turnable ladder into the given direction with a speed given by the corresponding speed signal. The actuating unit 16 can also comprise electric motors or other kinds of actuators or driving units.

(3) By the arrangement described above, the amount of deflection of the input device is turned into a corresponding movement of the turnable ladder with a speed determined by the deflection of the input device.

(4) To each aerial apparatus, like a turnable ladder in the present embodiment, there are certain restrictions for a speed of movement, depending on different parameters, like the extension range of the turnable ladder, the present acceleration at different points, the mechanical load, for example, the weight measured at the tip of the ladder, bending forces acting on the ladder, etc. One further speed limiting factor may also be the distance of the ladder to an external object. For example, it could be determined to move the ladder slowly near an object, to prevent the danger of a collision of the ladder with the object.

(5) To determine the possible maximum speed for the movement of the ladder, determining means are provided that comprise sensors 18, like speed sensors, acceleration sensors, weight sensors, load sensors and/or distance sensors for determining a distance to an object. The determining means may further comprise a calculation unit 20 for calculating a possible maximum speed from the sensor data measured by the sensors 18 and/or by other predetermined data related to construction parameters of the turnable ladder to be controlled.

(6) The control system 10 further comprises restricting means 22 for counteracting the deflection of the joystick 12 according to the possible maximum speed determining by the determining means 18, 20. In the present embodiment, this counteraction is provided by applying a restoring force according to the determined possible maximum speed to the joystick 12. This restoring force acts to restore the joystick 12 against the deflecting force applied manually by the operator. By the application of the restoring force, the joystick 12 is forced back into its neutral position to decrease the amount of its deflection and the lower the speed set by the joystick 12. The restoring force gives a haptic feedback to the operator, because the operation of the joystick 12 is only possible against the restoring force applied by the restriction means 22. For this purpose, the restriction means 22 may comprise motors or any other driving means to apply the restoring force. The force applied by these motors or driving means is set according to determined possible maximum speed, as described before.

(7) In the present control system 10, there is a direct feedback informing the operator about the present speed situation of the turnable ladder, because the possible maximum speed is determined in real time and for the present operation situation and he is informed immediately at any point of time about the possible maximum speed. Exceeding the present possible maximum speed can be prevented effectively by applying a restoring force that is high enough. This direct feedback effect can also be described as a “force feedback”.

(8) According to a different embodiment of the present invention, the restricting means 22 is provided to limit the deflection of the input device according to the determined possible maximum speed. In this embodiment the input device, like a joystick 12, can be moved within certain limits freely and without the application of any restoring force. However, the limits of this movement are set according to the possible maximum speed that has been determined by the determining means 18, 20 on the basis of the sensor data and predetermined data related to construction parameters of the aerial apparatus to be controlled. According to the present situation of the aerial apparatus, the limits of the movement of the input device can be adapted dynamically in real time corresponding to the present possible maximum speed.

(9) In the control system 10 of this embodiment, the joystick 12 as one example of a manually operable input device is deflected in at least one spatial direction by a deflection force applied by an operator, and the amount of deflection of the input device is converted into a corresponding speed signal. The turnable ladder is one example of the aerial apparatus is moved with a speed corresponding to the speed signal. During operation, a possible maximum speed of movement of the aerial apparatus is determined, and the deflection of the input device is counteracted or limited according to determined possible maximum speed.

(10) In the present embodiment the restoring force according to the determined possible maximum speed is applied to the joystick 12 acting to restore the joystick 12 against the deflecting force applied by the operator. The possible maximum speed can be determined on the basis of measured sensor data and predetermined data related to construction parameters of the aerial apparatus to be controlled.

(11) This invention can be implemented advantageously in a computer program comprising program code means for performing one or more steps of such method, when such program is run on a computer. For this reason the patent shall also cover such computer program and the computer-readable medium that comprises a recorded message, such computer-readable medium comprising the program code means for performing one or more steps of such method, when such program is run on a computer.

(12) Many changes, modifications, variations and other uses and applications of the subject invention will become apparent to those skilled in the art after considering the specification and the accompanying drawings which disclose preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by this invention.

(13) Further implementation details will not be described, as the man skilled in the art is able to carry out the invention starting from the teaching of the above description.