Self-righting mechanism

The self-righting mechanism (or srimech, derived from the words self-righting mechanism) is something of an essential in Robot Wars. In its simplest terms, it is a device used to flip a robot back onto its wheels if it gets flipped over. Although the first attempt to self-right in the UK Series was by Chaos, after being flipped over by Matilda in Series 2, the first successful srimech in the UK Series was used by Cassius also in Series 2, where it used its flipper to right itself after being overturned by Sir Killalot.

The term was coined by Rex Garrod after Cassius self-righted for the first time.

Powering
Usually, self-righting mechanisms are powered by either pnuematics (usually as part of a flipping weapon (Chaos 2 and Cassius were some of the first robots to have utilised these systems) or by an electric motor powered by the battery (Hypno-Disc and Panic Attack used these rather rare systems to great effect). However, there are also occasionally self-righting mechanisms powered by other means. Razer's self-righting wings are a good example-they were moved up and down by a steel cable attacked to the weapon, allowing it to self-right, as well as give its infamous "salute".

Types
During the shows history, there were three different sorts of Srimech.

Weapons
One of the ways a robot could self-right was through use of its own weapon. This was in fact the original UK Robot Wars srimech, as Cassius used its flipping arm to right itself, and Chaos could also right using its flipper (albeit it didn't on its only attempt). After Series 2, more robots began to use their flippers to self-right, and most robots with flippers, like Firestorm, Bigger Brother and Dantomkia, were capable of self-righting easily. In Series 4, Iron Awe became the first robot to self-right using an axe, and this was followed by others such as Dominator 2 and Terrorhurtz The advantage of self-righting through use of a weapon, such as flippers or axes, is that focus can be put on the weapon itself without having to make room for a secondary feature to right the robot. The main disadvantage, however, is that it depleted the effectiveness of the weapon after a while, and if the weapon power ran out, the robot would no longer be able to self right. This ultimately cost robots like Chaos 2 in Series 5 and 6 and Tsunami in Series 7.

Robots with flipper srimechs
Robots are listed alphabetically. Robots that are not heavyweight are listed with a green background.

Robots with other weapon srimechs
Robots are listed alphabetically. Robots that are not heavyweight are listed with a green background.

Seperate Mechanisms
Not every weapon was designed to right the robot, so often an alternative mechanism was used for robots that did not posess flippers or axes. A huge range of features were used across the shows history, including the side-bar of Hypno-Disc, the rear lid of Panic Attack, the side spikes of X-Terminator, the rollcage of Spikasaurus and, most notably, the "wings" of Razer.

These srimechs had advantage in that they did not detract from the robot's weapon, but at the same time they could often be easily targeted and were prone to failure if enough damage had been caused. This was of particular relevence to Panic Attack, who's self-righting lid broke after Refbot tried to free it from the arena wall in the Commonwealth Carnage in Extreme Series 2. The lid was removed soon afterwards.

Body Shape
A third, rarer form of self-righting came from the robot's body. Some robots, such as Velocirippa and Mega Morg were designed so that no matter how much it was flipped, it would always be able to roll back onto its wheels, in a similar manner to the rollcage feature. The first robot that had this feature was Ivanhoe in Series 2.

Although extremely effective if designed right, it was difficult to get that right design. It was also possible to become stranded if the robot was flipped over in just the right position (as Robochicken proved in Series 7, flipping Mega Morg straight into its back on a frontal attack), or there was not enough momentum behind the flip (which cost Ivanhoe as it was pushed onto its side by G.B.H.).