Ovládání strojů a zařízení

Při  návrhu je vhodné si ujasnit základní parametry:

  • v kolika osách bude chtít zařízení ovládat (1–6 os)
  • způsob ovládání: prsty, palcem, dlaní
  • způsob montáže: na stůl, do panelu zepředu, do panelu zezadu
  • omezení možnosti polohy (kruhové, hranaté, bez možnosti meziosé)
  • tvar páky
  • elektrický výstup

Kategorie

TRY52

Joysticky

Převodníky rozhraní joysticku

Průmyslové joysticky nebo také pákové ovladače hrají důležitou roli při ovládání různých zařízení. Můžeme je rozdělit na proporcionální se spojitým výstupem, spínačové a kombinované. Mezi proporcionální ovládače patří potenciometrické magnetické s Hallovým snímačem. Rozdílné konstrukční provedení, velikost a robustnost předurčují tyto joysticky k použití v nejrozmanitějších odvětvích průmyslu – řízení pohonů kolejových vozidel, bagrů, řízení robotů, souřadnicových stolů, kamerových systémů, ale i tak citlivých přístrojů, jakým je např. oční laser v medicíně.

 

U kategorie Ovládání strojů a zařízení Vás nejvíc zajímá

Průvodce joysticky

Applications for joysticks - the right design choice

To define the best joystick for your application, the first step is to choose the size. In most cases, this will already allow you to narrow down the pre-selection of products. The designs of the various joysticks can be divided into the following categories: Thumb, Finger, Hand and Desktop Joysticks. Since each of these sizes was developed for fundamentally different applications, selecting the right type is usually straightforward.

Thumb joysticks are the smallest type

Thumb-Joystick-Control
A classic application is remote controls, where an operator has to hold a housing in place, leaving his hand free for the input movement. The control is therefore typically done with the thumb. Thumb joysticks are also installed in control panels or in large handheld joysticks because space is often limited and the dimensions of thumb joysticks are not much larger than those of buttons and switches.

Finger joysticks are the all-rounders in the medium-size range

These joysticks provide the user with the highest operating precision due to the fact that the human fingers or fingertips can exercise the best control when operating the handle.  The application possibilities are very diverse and therefore the variety of finger joysticks is also the largest. It is in applications for control of medical equipment, surveillance cameras or mobile machines that this design shows its strengths.
Finger-Joystick-Control

Hand joysticks represent the largest type

Hand-Joystick-Control
In general, it can be said that the mechanical stability increases with size. However, the application also places increased demands on the product. Hand joysticks are therefore used in the heavy-duty sector for controlling cranes, construction machinery and other large vehicles and systems. Here the safety requirements are particularly high and usually redundant electronics and sensor technology is necessary. Accordingly, investment costs increase with the size of the joystick.

Desktop joysticks represent a special group

As a rule, these are integrated finger joysticks in desktop housings, which usually offer a few buttons for additional functions in the housing.  These input devices cover the rather large demand for stationary applications with already permanently installed finger joysticks. The area of video surveillance is particularly worth mentioning. Nowadays only USB variants are of importance here, because the input information is usually transferred immediately to a computer.
Desktop-Joystick-Control

Axis configuration

The selection of the available degrees of freedom

Degrees-of-freedom
Each joystick model has certain limitations regarding the available number of degrees of freedom and the freedom of movement for operation. The degrees of freedom are called axes for joysticks. Most models offer 2 axes, i.e. the handle can be moved in X and Y direction (forward/backward, left/right). In addition, the handle can also be rotated in some models. This is called the Z-axis and allows the input of a total of 3 degrees of freedom in simple designs. Most thumb joysticks offer a maximum of 2 degrees of freedom. Many finger joysticks are available as 3-axis joysticks. However, even more axes can be implemented for hand joysticks. In the head plate of these joysticks there is space for a lot of input elements and thus for additional degrees of freedom.
An exception to the range is our SpaceMouse® Module: here the control handle can be deflected in all three directions - in addition, tilting/rotation of each direction is possible. This results in a total of 6 degrees of freedom, allowing direct, intuitive navigation and control in 3-dimensional space.

Axis configuration - limiter selection

The freedom of movement of the main axes can be restricted in almost all models. In some applications, when the first axis deflects, the second axis should be blocked ("plus" limiter). In other cases the simultaneous deflection should be possible only to a reduced extent (round limiter). The square limiter offers full freedom of movement. Some hand joystick models offer the possibility of locking in the middle or at deflection. For this, see the section "Reset characteristics and haptics".
Limiter for joysticks

The handle - interface to the user

Handles for Joysticks
The configurability of the handles increases with the size of the model. Thumb joysticks offer many handle shapes and a few offer the possibility to switch with pressure on the handle. With finger joysticks, the variety increases further and several push buttons are already possible. Hand joysticks offer the largest variety of handle options. In fact, almost all models are customized for the application. The configurability is usually higher than indicated on the data sheets. Feel free to contact us to get the best solution for your application!

Selection of sensor technology

Contactless, potentiometric or by switch?

Two technologies are of importance for industrial joysticks today: Hall sensors and potentiometric sensors.
Hall sensor technology is a contactless technology in which the sensor detection of the deflection is contactless. This has the advantage that there is practically no wear and tear and therefore no change in sensor behaviour over the entire running time. If there are no particular reasons for excluding this technology, such as strong electromagnetic interference in the application environment, Hall sensors are usually chosen.
Hall-sensor
Potentiometer-rotativ-connection
Potentiometric sensors use wiper and resistance elements for sensory detection. Only high-quality, so-called precision potentiometers meet the most demanding requirements for quality and lifespan. The advantage of this technology lies in its insensitivity to external interference fields. Joysticks with potentiometric sensors are particularly popular in medical technology, where the requirements for immunity to X-rays, other interference fields and electrostatic discharges are very high.
If a continuous output signal between minimum and maximum deflection is not required in applications, switch sticks are a good choice. These are only equipped with switches that detect the deflection of the joystick. Thanks to their simple and straightforward design, switches are very insensitive to interference and disturbances. However, the number of switching operations is limited and usually results in a shorter lifespan. A special situation is the use of switch sticks for switching high currents directly via the joystick, which otherwise has to be done with an external relay.
Switch
In general, it should be noted that the sensor technology used does not say anything about the quality and durability of the joystick's mechanics. It can happen that the mechanics of low-cost components fail long before the sensors, so the sensor technology should not be overrated. In uncomplicated cases we recommend compact Hall joysticks, as these are the easiest to integrate today and are suitable for most applications. Safety-critical applications often require redundant designs with two sensor elements per axis. Almost all of our models are optionally available as redundant versions.

Return mechanism and haptics

As a rule, the application determines whether the joystick should return to its initial position when not actuated (by spring return) or whether it should remain in the last position in one or more deflection directions (friction brake, optionally also by detent positions). Most modern joystick models are equipped with a central spring. This spring returns the operating lever to the middle position for both deflection directions. The strength of the spring can be adjusted. For constructive reasons, no further adjustments such as an additional friction brake can be implemented. If the application requires friction brakes or detent positions, special models must be used, whose design is larger and more complex, but which are therefore more flexible for such adaptations.
Spring-return

Outputs and interfaces - analogue or digital?

Outputs-and-interfaces
Almost all joystick models offer analogue voltage outputs in the range of 0-5 V. These are usually the basic versions of the products and accordingly the most economical versions. Since potentiometers are basically passive components, joysticks with potentiometric features usually only offer analogue outputs. For some models only analogue versions are available, which are sufficient for most applications. Modern models with non-contact sensors offer additional digital interfaces, such as pulse width modulation (PWM), USB, RS232 (serial) and CAN bus variants. The interfaces offered are very different and are only listed for certain series. Therefore, it pays off to look only at these products when an interface is specified.

Tips and hints

Circuit

Depending on the sensor technology used, the evaluation electronics must be designed very differently. Hall-effect joysticks use integrated circuits as sensor elements, which are installed on printed circuit boards within the housing of the joysticks. Depending on the circuit board design, different operating parameters must therefore be observed, which can be found on the data sheet. This therefore also applies in general to the bus systems offered. In potentiometric models with analogue outputs, however, the angle sensors are passive components (conductive plastic potentiometers) and the models are usually not equipped with control electronics. The connections lead directly to the potentiometers, which must be operated in a voltage divider circuit in order not to damage the sensors. Please take special care that no relevant current flows through the outputs, as this could damage the potentiometer wipers.

Environmental influences

Joystick-dirt-and-water
Vibrations, mechanical overload, heat, aggressive substances, etc. can endanger the operational safety of input elements. The resistance of the individual models varies greatly and generally higher prices are justified by higher resistance or by better technical specifications. In general: The specified protection classes are indicated above the panel. If moisture is expected below the seal, products that allow optional sealing of the electronics must be selected. Please contact us if you have this requirement. The specified operating temperatures are used as reference values for the recovery properties of the mechanics and for the elastomers used for the sealings, but also for the electronic components. Most joysticks also function at lower temperatures than those specified in the data sheet. Especially for safety-relevant applications we advise against operating the joysticks outside these limits.

Mounting

Most models can be mounted into a panel from above. Typically, the base, the joystick pot, is round and is fixed by 4 screws. On some models, the handle fits through the recess in the panel and can therefore also be installed in the panel from below. Depending on the degree of protection and the general type of construction, the covers of the mechanics (rubber bellows) are either screwed together with a cover ring to form a seal or separate seals are supplied to ensure the seal in the panel.

Product customizations

The MEGATRON team has decades of experience as a reliable partner for industrial and medical technology customers. Our particular strength is the customer-specific adaptation of products. Especially the optimal adjustment of joysticks to the application is often required for small to medium quantities, as niche markets are also served here. Joysticks offer a wide range of adaptation possibilities. Depending on the feature to be modified, these adaptations can be carried out even for small quantities. Please contact us and describe your request - we will find the best solution for your application!
Product customization for hand joysticks
Product customization for finger joysticks